Term
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Definition
| The belief that an embryo forms "from scratch" as opposed to the theory of preformation. |
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Term
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Definition
| The belief that embryos come with all of their organs in miniature form. Disproved when Wolff saw the blood and heart form in embryos. |
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Term
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Definition
| Become the gill apparatus in fish but the jaws and ears in mammals. Discovered by Rathke. |
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Term
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Definition
| separates embryo in left and right halves and instructs endoderm to become the nervous system. |
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Term
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Definition
| Diagrams that show what each cell becomes by combining cell lineage information. |
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Term
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Definition
| Grafting radioactive cells into embryos in order to track their path. |
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Term
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Definition
| tightly connected in sheets or tubes |
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Term
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Definition
| Unconnected and operate as independent units |
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Term
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Definition
| Joins the neural tube to the epidermis. |
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Term
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Definition
| An abnormality caused by genetic events and often appear in multiples as Syndromes. |
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Term
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Definition
| Abnormalities caused by exogenous agents (chemicals, viruses, radiation or hyperthermia). These agents are called TERATOGENS hence the study of teratology. |
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Term
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Definition
| rapid mitotic divisions immediately following fertilization. Divides zygote cytoplasm into blastomeres, which form a sphere called a blastula. |
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Term
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Definition
| Creates the three germ layers as the blastomeres rearrange themselves. |
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Term
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Definition
| After gastrulation, the blastomeres interact and rearrange into tissues and organs. Many cells undergo long migration during this process. |
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Term
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Definition
| Transforming from a larva into a sexually mature adult in many species. |
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Term
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Definition
| Forming of germ cells and later gametes. |
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Term
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Definition
| The bottom half of a forming egg that usually contains more yolk. Found in non-placental animals. Formed by holoblastic cleavage. |
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Term
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Definition
| The upper half of an egg without much yolk. |
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Term
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Definition
| A fluid filled cavity formed in the animal hemisphere that allows cell movement during gastrulation. |
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Term
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Definition
| The point opposite from sperm entry that forms a dimple, becomes a ring and cells that migrate through it ultimately become the mesoderm. |
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Term
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Definition
| The stage of embryo after the upper ectodermal cells that don't become epidermis begin to form the nervous system. The beginning of organogenesis. |
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Term
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Definition
| Precursors to frog back muscles, spinal vertebrae and dermis. |
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Term
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Definition
| Stores nutritive proteins |
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Term
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Definition
| Contains the fluid bathing the embryo. |
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Term
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Definition
| Collects waste materials from embryonic metabolism. |
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Term
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Definition
| Interacts with the outside environment and selectively allows materials to reach the embryo. |
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Term
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Definition
| Multicellular organisms that go through an embryonic development. |
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Term
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Definition
| Mouth forms first from the blastopore. |
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Term
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Definition
| Develop anus first from the blastopore |
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Term
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Definition
| The genotype encodes for not one particular phenotype, but a number of possible phenotypes |
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Term
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Definition
| The idea that the environment is the determining factor as to which of the phenotypes will be expressed. |
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Term
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Definition
| The development of specialized cell types |
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Term
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Definition
| A cell is not phenotypically different, but its fate is now determined. Split up into specification and determination |
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Term
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Definition
| The stage at which a cell will continue to differentiate when placed in a neutral environment. |
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Term
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Definition
| A cell will continue to develop autonomously even if placed in another tissue or area of the embryo. |
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Term
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Definition
| If a blastomere is separated, it will produce the same types of cells that it would have if it was still part of the embryo and the embryo which it was taken from will lack these cells. |
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Term
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Definition
| Describes how the embryo appears to be made up of independent, self-differentiating parts. |
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Term
| Morphogenetic determinants |
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Definition
| In autonomously specified embryos these proteins or mRNAs are put in different regions of the egg cytoplasm and apportioned to the different cells as it divides. They determine the cell type. |
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Term
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Definition
| Method of commitment used by insects in which cell division is not complete in early embryos, rather, the nuclei divide resulting in many nuclei per cytoplasm. |
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Term
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Definition
| Egg Cytoplasm containing many nuclei |
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Term
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Definition
| Proteins that give positional information by creating concentration gradients with the highest at the point of synthesis. |
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Term
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Definition
| A map based on ratios of morphogens. |
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Term
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Definition
| Mode of commitment which depends on the conditions the cell is in. The once versatile cell is affected by the cells around it. |
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Term
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Definition
| If a group of embryonic cells are removed, an embryo that uses conditional specification can compensate for missing parts. |
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Term
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Definition
| Technique in which one destroys a portion of the embryo and then observes the development of the impaired embryo |
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Term
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Definition
| Technique in which one removes a portion of the embryo and then observes the development of both the partial embryo and the isolated part |
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Term
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Definition
| Technique in which one observes the development of the embryo after replacing an original part with one from a different region of the same embryo |
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Term
| Transplantation Experiment |
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Definition
| Technique in which one portion of the embryo is replaced by a portion from a different embryo. Used in constructing the first fate maps. |
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Term
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Definition
| A field in which all the cells have a position and fate specified with respect to the same set of boundaries. These cells will give rise to their specified cells even if transplanted. |
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Term
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Definition
| Cells capable of dividing indefinitely and able to divide into more specific cells |
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Term
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Definition
| Can give rise to ectoderm, endoderm, mesoderm, and germ cells. Cannot give rise to surrounding embryo tissue like placenta (totipotent) |
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Term
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Definition
| Give rise to a smaller portion of cells such as hemangioblasts give rise to blood vessels, blood cells, and lymphocytes. |
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Term
| Progenitor or Precursor Cells |
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Definition
| No longer stem cells, these are limited in what they can form. Ex: myeloid progenitor generates different types of blood cells. |
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Term
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Definition
| Ectodermal cells have a positive affinity for mesodermal cells and negative for endoderm. Mesoderm has positive for both. This causes them to arrange in order of endoderm mesoderm ectoderm. |
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Term
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Definition
| Reconstruction of complex tissues from individual cells. Experimentally skin tissue from a mouse embryo was destructed in water and reconstructed themselves correctly. |
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Term
| Differential Adhesion Hypothesis |
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Definition
| Explains cell movement and sorting based on thermodynamic principals. If A-A bonds are stronger than A-B and B-B bonds, A will be more tightly connected towards the middle. |
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Term
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Definition
| Calcium Dependent Adhesion molecules. They establish and maintain intercellular connections and create spatial segregation. Anchored by Catenins. |
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Term
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Definition
| Bind to cadherins and the actin cytoskelton of the cell and therefore integrate epithelial cells into a mechanical unit. |
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Term
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Definition
E-cadherin: all early mammalian embryos
P-cadherin: helps placenta stick to the uterus
N-Cadherin: found in cells developing the central nervous system |
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Term
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Definition
| Outer cells that bind to the uterus |
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Term
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Definition
| Generate the embryo and eventually become the mature orgainism |
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Term
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Definition
| annealing single-straded pieces of DNA and RNA to allow complementary strands to form double-stranded hybrids |
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Term
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Definition
| enzyme that makes DNA out of mRNA |
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Term
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Definition
| use RTase to convert mRNA to cDNA, use PCR. cDNAs are then robotically placed on a grid and hybridized to two targets flourescently labeled. Mix DNA in question to probe cDNA and measure color intensity with image processing. |
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Term
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Definition
| Similar to microarrays but can be visually interpreted. |
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Term
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Definition
| Antisense mRNA probe labelled with dye or made radioactive is hybridized with the mRNA in the organ. The organ is usually fixed and sometimes sectioned onto a slide. |
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Term
| Whole-mount in situ hybridization |
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Definition
| Staining the whole or part of the embryo. Shows large regions of gene expression. |
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Term
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Definition
| High voltage pulse pushes DNA into desired cells` |
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Term
| Transposable Element or Retroviral vector |
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Definition
| Mobile regions of DNA that integrate themselves into the genome. |
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Term
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Definition
| naturally occuring transposable element DNA that can integrate into any region of Drosophila. |
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Term
| Embryonic Stem cells (ES cells) |
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Definition
| Inner cell mass blastomeres cultured in vitro and are almost totipotent. |
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Term
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Definition
| An organism containing some gametes from the treated ES cell. Becomes the P generation essentially. |
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Term
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Definition
| Replaces wild type alleles with mutant ones. |
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Term
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Definition
| DNA repair and replication enzymes incorporate mutant genes in place of a normal copy. Selected with drugs usually. |
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Term
| Morphollino Antisense Oligomers |
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Definition
| Rather than 5carbon sugars, these pseudo nucleic acids contain 6member morpholine rings. They have resistance to nucleases , therefore are able to stay intact and functioning longer. |
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Term
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Definition
| sequence-specific targeting of mRNA that inhibits its expression by using dsRNA with the same sequence as mRNA. Tricks the cell into thinking its own mRNA is a virus. |
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Term
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Definition
| Pieces of dsRNA that bind to a complex that destroys any RNAs bound by that fragment. |
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Term
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Definition
| Binds RNA polymerase and is often upstream from -25 to -100BP of Transcription Initiation Site |
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Term
| Transcription Initiation Site |
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Definition
| The cap sequence where the 5' cap made of sideways Guanine will be placed. |
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Term
| Tranlation Initiation Site |
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Definition
| ATG. Many (50 in B globin) BP down from the Transcription Initiation Site. |
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Term
| 5' UTR or Leader Sequence |
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Definition
| Section in between initiation sites for transcription and translation. Determines how fast translation is initiated. |
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Term
| Translation Termination Codon |
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Definition
| TAA. Dissociates the ribosome and releases the protein. |
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Term
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Definition
| Transribed, but not translated. Has AATAAA followed by the poly-A tail after processing. This tail confirs stability, allows mRNA to exit the nucleus, and permits it to be translated into protein. |
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Term
| Transcription Termination Sequence |
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Definition
| about 1000 BP after the AATAAA site. |
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Term
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Definition
| Original transcription product contains cap sequence, 5'UTR exons, introns, and 3'UTR. Gets sent to processing to add the cap and poly A tail. |
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Term
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Definition
| RNA polymerase binding sites on DNA that initiate transcription. Contain the TATA box -30BP. Flanked by CpG islands, and/or Basal transcription factors to help recognize the correct TATA and bind. |
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Term
| Basal Transcription Factors |
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Definition
TFIID-Recognizes TATA box.
TBP-TATA binding protein.
TFIIA-binds to TFIIB |
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Term
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Definition
| Proteins that bind to enhancer or promoter regions and interact to activate or repress the transcription of a particular gene. |
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Term
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Definition
| Domain on a Transcription Factor that recognizes a particular DNA sequence |
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Term
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Definition
| The second Transcription Factor domain that activates or suppresses the transcription of the gene whose promotor or enhancer it has bound. Usually works with RNA polymerase binding proteins or those that modify histones. |
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Term
| Protein-Protein Interaction Domain |
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Definition
| 3rd Transcription Factor domain that allows activity to be modulated by TAFs or other TFs. |
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Term
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Definition
| Sequences that bind proteins to prevent an enhancer from activating an adjacent promotor. Often located between the enhancer and the promoter. |
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Term
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Definition
| DNA regulatory elements that repress transcription on part of a particular gene. |
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Term
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Definition
| Enzymes systematically change Cytosine followed by Guanosine into 5-methylcytosine in promotor areas they wish to inactivate. This stablizes nucleosomes and prevents TFs from binding. |
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Term
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Definition
| The process of ensuring that males and females recieve equal amounts of gene products despite females having twice the X information. Accomplished by:Transcription rate of male X doubling,Inactivation of one X |
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Term
| X Chromosome Inactivation |
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Definition
| Dosage compensation by inactivation of a female X chromosome. |
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Term
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Definition
| Inactivated X chromasome that remains condensed througout most of the cell cycle and replicates later than most of the other chromatin. |
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Term
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Definition
| The heterochromatic X chromosome that can often be seen on the nuclear envelope of a female cell. |
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Term
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Definition
| Complexes made of snRNA and proteins that bind to splice sites or consensus sequences on nRNA. |
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Term
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Definition
| The small nuclear RNA and proteins that make up spliceosomes. |
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Term
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Definition
| Different proteins encoded by the same gene. Often one gene can make a family of proteins. |
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Term
| Eukaryotic Initiation Factor-4E |
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Definition
| Binds the 5' cap in mRNA processing before it can leave the nucleus. |
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Term
| Cytoplasmic Polyadenylation-element-binding protein CPEB |
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Definition
| Protein that attaches to the UUUUAU sequence in the 3' UTR. This is the first part in attaching the 3' and 5' ends. |
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Term
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Definition
| Short RNA sequences of about 22 nucleotides made from longer precursers from independent transcription units, or from the introns of other genes. |
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Term
| RNA-induced silencing complex (RISC) |
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Definition
| miRNA that has been packaged with a series of proteins. This binds to the 3' UTR and inhibits translation. |
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Term
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Definition
| Proximate interaction between cells or tissues in which one changes the behavior of its neighbor. |
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Term
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Definition
| The tissue that produces a signal that changes the cellular behavior of the other. |
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Term
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Definition
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Term
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Definition
| The actively acquired condition in which cells have the ability to respond to a specific inductive signal. |
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Term
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Definition
| A necessary product that allows the responder to sensitive to the inductive signal. |
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Term
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Definition
| Interactions in which the inducer becomes the induced. |
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Term
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Definition
| An inducing signal is necessary for initiating new gene expression in the responding cell. Without this signal, it will not develop the same. |
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Term
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Definition
| The responding tissue only needs an environment that allows its expression. |
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Term
| Epithelial-Mesemchymal Interactions |
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Definition
| Examples include development of the optic vesicle and lens. |
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Term
| Regional Specificity of Induction |
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Definition
| When recombination of epithelial and mesenchymal tissues leads to outcomes different from what the epithelium was programmed for. Example: messenchyme from the wing leads epithelium to form a feather while that of the foot leads it to form scales. |
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Term
| Genetic Specificity of Induction |
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Definition
| The responder can only comply so much as its genome allows. Example: swapped frog and newt epithelium formed the mouth which was appropriate for their original genome, not that which the messenchyme would have signaled. |
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Term
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Definition
| Cell membrane proteins on one cell surface interact with receptor proteins on an adjacent cell. |
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Term
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Definition
| When surface proteins can diffuse over small distances to induce changes. |
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Term
Paracrine Factors
Growth and Differentiation Factors (GDFs) |
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Definition
| Proteins capable of diffusing and inducing other proteins. |
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Term
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Definition
| Hormones that travel through the blood unlike paracrine which are secreted into the immediate space surrounding the cell. |
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Term
| Paracrine Factor Families |
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Definition
1) fibroblast Growth Factor FGF family
2) Hedgehog family
3)Wingless or Wnt Family
4)TGF-B family including TGF-B, acgtivin, bone morphogenic proteins BMPs, and Vg1 families as well as other proteins. |
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Term
| Signal Transduction Cascades |
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Definition
| Pathways of responses to the paracrine factors. Usually respond by regulating TFs or the cytoskeleton. |
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Term
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Definition
| A type of Signal Transduction Cascade in which a ligand (the paracrine factor) binds to the outer domain of a transmembrane protein. Inside the cell, this causes an enzymatic response in which the receptor can now catalize phophorylation in proteins that will eventually activate a dormant TF or cytoskeletal protein. |
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Term
| Fibroblast Growth Factor FGF gene family |
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Definition
| Gene family that includes members responsible for things like regeneration, blood vessel formation, and skin development. They work by activating RTKs called Fibroblast Growth Facts Recptors FGFRs so that the kinase is activated and will phosphorylate certain proteins. |
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Term
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Definition
| An inactive GDP bound receptor. As part of the RTK Signal Transduction Pathway it then stimulates the adaptor protein to activate the GNRP. |
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Term
| GNRP Guanine Nucleotide Releasing Factor |
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Definition
| Protein that exchanges a phosphate from GTP to transform the G protein's GDP form into a bound GTP. This then transmits signal to the next molecule and is hydrolyzed back into GDP. |
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Term
| GAP: GTPase-activating Protein |
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Definition
| Complexed with the Ras protein so it can return the G protein back into its inactive state. |
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Term
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Definition
| A paracrine protein that binds to and activates the Kit RTK. Eventually leads to expression of White gene. |
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Term
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Definition
| Includes indian hedghog (ihh) sonic hedgehog (shh) and desert hedgehog (dhh). These proteins are often used to induce particular cell types and create bouundaries between tissues. they must be complexed with cholesterol to function. They bind to a receptor called Patched. |
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Term
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Definition
| hh proteins bind to patched which is bound to Smoothened signal transducer. Upon binding to hh, Patched releases Smoothened which releases Cubitus interuptis (Ci) protein which was inhibiting transcription. Upon being released, Ci can enter the nucleus and activate the genes it was previously repressing. |
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Term
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Definition
| Cystein-rich glycoproteins named for "wingless" and "integrated." These induce dorsal cells of somites to become muscle and help with specification of the midbrain, establish polarity in limbs and promote proliferation of stem cells. |
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Term
| Apoptosis--programmed cell death |
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Definition
| Cells are programmed to die at certain times, such deaths allow for much spacing. |
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Term
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Definition
| A family of juxtacrine factors that remain bound to the inducing cell surface. One pathway has proteins that activate neighboring cells that contain the Notch protein. When they contact, it enables part of its cytoplasmic domain to be cut off by Presenilin-1 protease. Now cut, it can enter the nucleus and activate the CSL transcription factor to activate their genes. Considered a TF tethered to the membrane. |
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Term
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Definition
| macromolecules secreted by cells into their immediate environment. Used for cell adhesion, migration, and forming epithelial sheets and tubes by strong or weak binding. Made up of collagen, proteoglycans, and specialized glycoproteins. |
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Term
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Definition
| Part of the extracellular matrix that delivers paracrine factors. made of core proteins covalently bonded to glycosaminoglycan polysaccharide side chains. |
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Term
|
Definition
| A large glycoprotein dimer that serves as a general adhesive and serves in migration. |
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Term
|
Definition
| A closely knit sheet made primarily of Laminin and type IV collagen. |
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Term
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Definition
| A family of receptor proteins that integrate extracellular and intracellular scaffolds so they can coordinate. Upon binding they can stimulate the RTK pathway. |
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Term
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Definition
| Each step in the pathways can be seen as a regulatory point as as well as potential intersection. In cross-talk, two signaling pathways reinforce each other. |
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Term
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Definition
| The cytoplasmic components including specific proteins and mRNAs that autonomously localize to make the PGCs. |
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Term
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Definition
| Blastomere chromosomes fragment into dozens of pieces before the cell divides. This causes only a portion of the original chromosome to survive. |
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Term
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Definition
| Proteins that include transcription inhibitors and RNA binding proteins which enter into the P4 blastomere. |
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Term
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Definition
| nuclei that PGCs form in the posterior pole of the cellularizing blastoderm. |
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Term
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Definition
| Cytoplasm surrounding the pole cells that is made up of mitochondria, fibrils, and polar granules. Found in Insects and homologue of gcl in mammals. |
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Term
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Definition
| Formed by germ cells, they divide asymmetrically to produce another stem cell and a cystoblast. |
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Term
|
Definition
| Incomplete cytokinesis bridges that separate the clusters after four mitotic division. |
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Term
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Definition
| The egg chamber containing the cell that will become the oocyte. |
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Term
|
Definition
| Those cells in the ovariole that are connected to the oocyte via ring canals and feed it RNAs and proteins |
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Term
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Definition
| Germ cell-less. This gene encodes mRNA found in the pole plasm. Without it, later generations cannot form germ cells. |
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Term
| Polar granule component Pgc |
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Definition
| A noncoding RNA that inhibis transcription by preventing phosphorylation of RNA polymerase. If mutated, the cell would express genes of their neighboring somatic cells. |
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Term
| Posterior Group Determinants |
|
Definition
| Another pole plasm component including the Oskar protein which instructs nuclei to form germ cells. |
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Term
|
Definition
| Greek for "thin thread" this is a stage of meiosis in which the chromatin stretch out thinly and it is not possible to identify individual chromosomes |
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Term
|
Definition
| Greek for "joked threads", this is a stage for homologous chromosomes to pair side by side in Synapsis. |
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Term
|
Definition
| A Ladder-like structure with central element and two lateral bars, the chromosomes join. |
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Term
|
Definition
| Four chromatids and the synaptonemal complex. |
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Term
|
Definition
| Greek for "thick thread" and is when the chromatids thicken and shorten. Crossing over may occur. |
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Term
|
Definition
| Exchanging genetic material between homologous chromatids. |
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Term
|
Definition
| Greek, "double threads". Crossing over can still occur, and the synaptonemal complex breaks down. Homologues separate. |
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Term
|
Definition
| Attachment points thought to represent regions of crossing over. |
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Term
|
Definition
| Greek, "moving apart" where the chromasomes remain joined only at the tips. |
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Term
|
Definition
| The chromosomes migrate here as the nuclear membrane breaks down. |
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Term
|
Definition
| A brief break in between telophase 1 and meiosis 2. |
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Term
|
Definition
| Protein glue that keeps sister chromatids together during mitotic prophase and metaphase. |
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Term
|
Definition
| Cytoplasmic connections between dividing cells. |
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Term
|
Definition
| Drosophila PGC receptor protein that helps detect concentration gradients of SDF 1 so the PGCs can migrate to the gonads. |
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Term
|
Definition
| Signaling protein in Drosophila from the gonads to attract PGCs so they can develop. |
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