Term
|
Definition
| rapid, early cell divisions in embryo |
|
|
Term
| What does cleavage accomplish? |
|
Definition
| multicellularity, regionalization, new cell-cell interactions, cell movement, partitioning of localized determinants |
|
|
Term
|
Definition
| volume of embryo stays same, but gets divided into more cells, increasing surface area |
|
|
Term
|
Definition
| involves just S phase (synthesis of DNA) and M phase (mitotic phase), no G1 or G2 gap phases like in somatic cells |
|
|
Term
| Maturation Promoting Factor (MPF) |
|
Definition
| required for mitosis, but activates anaphase promoting complex (APC) to degrade MPF after metaphase |
|
|
Term
|
Definition
| cyclin B and cyclin-dependent kinase (CDC2 or CDK2) |
|
|
Term
|
Definition
| cyclin B is degraded as cell exits M phase, so CDC2 is inactivated |
|
|
Term
| How many types of cyclin/CDC complexes are involved in cleavage? |
|
Definition
|
|
Term
| What regulates cleavage furrow positioning? |
|
Definition
|
|
Term
| What is the difference between astral microtubules and spindle microtubules? |
|
Definition
| astral microtubules extend outwards to cell membrane, while spindle microtubules attach to chromosomes during DNA replication |
|
|
Term
| What regulates contractile ring formation? |
|
Definition
|
|
Term
| How does G-protein Rho regulate formation of contractile ring? |
|
Definition
| directs actin polymerization and myosin activation |
|
|
Term
| Where is G-protein Rho localized when activated? |
|
Definition
| where contractile ring will eventually assemble |
|
|
Term
| Provide evidence for contractile ring formation dependence on Rho. |
|
Definition
| GFP-tagged Rho localizes to where contractile ring forms; C3 transferase injection inhibits Rho, and embryo can replicate DNA, but can't divide into cells |
|
|
Term
| Where does additional plasma membrane come from for cell division? |
|
Definition
| smoothing out of folds in membranes and from internal vesicles |
|
|
Term
| Provide evidence for the formation of new plasma membrane in cell division. |
|
Definition
| stain original membrane darker; lighter membrane shows as cleavage occurs |
|
|
Term
| Effect of yolk on cleavage |
|
Definition
| Cleavage is difficult in presence of a lot of yolk |
|
|
Term
| Two factors that dictate cleavage |
|
Definition
| completeness of cleavage (dependent upon amount & localization of yolk) and orientation of cleavage |
|
|
Term
|
Definition
| uniform yolk distribution, not a lot |
|
|
Term
|
Definition
| moderate amount of yolk, found in a gradient |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Radial cleavage orientation |
|
Definition
| perpendicular to previous cleavage |
|
|
Term
| Rotational cleavage orientation |
|
Definition
| cleavage rotates 90 degrees from previous cleavage |
|
|
Term
| Spiral cleavage orientation |
|
Definition
| top tier of cells rotates relative to bottom tier |
|
|
Term
|
Definition
| anus formed first, then mouth; radial cleavage |
|
|
Term
|
Definition
| mouth formed first, then anus; spiral cleavage |
|
|
Term
| Examples of deuterostomes |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Yellow crescent of ascidians |
|
Definition
| myoplasm that is inherited by cells that eventually become muscle |
|
|
Term
| What regulates the timing of midblastula transition? |
|
Definition
| nucleus to cytoplasm ratio |
|
|
Term
|
Definition
| when divisions slow and become asynchronous; embryos start making their own mRNAs |
|
|
Term
| Provide evidence that higher nucleus to cytoplasm ratio triggers midblastula transition |
|
Definition
| separate cytoplasm creating bridge that prevents nucleus from sharing; then hair loosened for mitosis to occur; one half had less nucleus than other, so one with high ratio underwent midblastula transition faster |
|
|
Term
| Type of cleavage in Drosophila |
|
Definition
| centrolecithal, meroblastic, superficial |
|
|
Term
| Type of cleavage in mammals |
|
Definition
| isolecithal, holoblastic, rotational |
|
|
Term
| Type of cleavage in echinoderms |
|
Definition
| isolecithal, holoblastic, radial |
|
|
Term
| Type of cleavage in birds |
|
Definition
| telolecithal, meroblastic, discoidal |
|
|
Term
| Type of cleavage in mollusks |
|
Definition
| isolecithal, holoblastic, spiral |
|
|
Term
| Examples of isolecithal, radial cleavage |
|
Definition
|
|
Term
| Examples of isolecithal, spiral cleavage |
|
Definition
| annelids, mollusks, flatworms |
|
|
Term
| Examples of isolecithal, bilateral cleavage |
|
Definition
|
|
Term
| Examples of isolecithal, rotational cleavage |
|
Definition
|
|
Term
| Examples of mesolecithal, radial cleavage |
|
Definition
|
|
Term
| Examples of telolecithal, bilateral cleavage |
|
Definition
|
|
Term
| Examples of telolecithal, discoidal cleavage |
|
Definition
|
|
Term
| Examples of centrolecithal, superficial cleavage |
|
Definition
|
|
Term
| How can translation be inhibited? |
|
Definition
| maskin protein or microRNAs |
|
|
Term
| What and where has to bind to DNA before RNA polymerase II can bind? |
|
Definition
| general transcription factors at TATA box |
|
|
Term
| How is RNA polymerase II released from complex of transcription factors to begin transcription? |
|
Definition
| a general transcription factor phosphorylates C-terminal tail of RNA polymerase II to release it |
|
|
Term
| How/where do transcriptional regulators interact with DNA? |
|
Definition
| interact at major grooves of double helix |
|
|
Term
|
Definition
| control rate and efficiency of transcription |
|
|
Term
|
Definition
| bind to regulatory transcription factors that then bind to the mediator complex; this complex then acts as a protein bridge to stabilize RNA polymerase II to increase binding and transcription efficiency |
|
|
Term
| What happens when myogenic factor (MyoD1) is overexpressed in non-muscle cells? |
|
Definition
| causes cells to adopt muscle-like fate |
|
|
Term
| What happens when eyeless is driven at various locations of a fly? |
|
Definition
| eyes form at these tissues |
|
|
Term
| What happens when Yamanak factors are expressed in terminally differentiated cells? |
|
Definition
| They revert back to pluripotent cells |
|
|
Term
| What are reporter constructs? |
|
Definition
| allows determination of where gene is transcribed; upstream regulatory DNA is fused with GFP, then delete region of regulatory DNA to see if expression is affected |
|
|
Term
| What is Dscam in Drosophila? |
|
Definition
| mRNA that is expressed in nervous system and can code for 30k+ proteins; allows for dendrites to be able to recognize different neurons if they have different Dscam isoforms |
|
|
Term
| What function does the 3' UTR serve? |
|
Definition
| regulates spatial localization of mRNA |
|
|
Term
| How is bicoid mRNA localized? |
|
Definition
| associates with dynein and is carried to minus end at anterior |
|
|
Term
| How is oskar mRNA localized? |
|
Definition
| associates with kinesin and is carried to plus end at posterior |
|
|
Term
| How is translation of maternal mRNAs inhibited? |
|
Definition
| maskin binds to and masks 5' cap; also prevents addition of polyA tail (mRNAs are then made in a loop conformation and can't be translated) |
|
|
Term
| How/where does Bicoid protein inhibit translation of caudal? |
|
Definition
| binds to 3' end of caudal mRNA and 5' cap to prevent attachment of transcription factors and polyA tail in anterior |
|
|
Term
|
Definition
| small RNAs that regulate mRNAs |
|
|
Term
| How does a microRNA degrade mRNA that is an exact match? |
|
Definition
| processed then cleaved into small fragments by Dicer; then associate with mRNA to degrade it |
|
|
Term
| How does microRNA degrade mRNA that is a close (but not exact) match? |
|
Definition
| processed then cleaved into small fragments by Dicer, then associate with mRNA to prevent translation |
|
|
Term
| What happens when fish are treated with Dicer morpholino? |
|
Definition
| shorter than normal, so miRNAs are necessary for normal development |
|
|
Term
| Provide evidence for the fact that miRNA is sufficient for normal brain development. |
|
Definition
| Dicer morpholino phenotype can be rescued by a single miRNA |
|
|
Term
| What is the pseudoautosomal region of X and Y chromosomes? |
|
Definition
| can undergo recombination |
|
|
Term
| Where is the testis determining factor located? |
|
Definition
| on Y chromosome, near pseudoautosomal region |
|
|
Term
| What happens if testis determining factor is located on X chromosome of XX individual? |
|
Definition
| person will form testicles |
|
|
Term
| What happens if testis determining factor is absent from Y chromosome of XY individual? |
|
Definition
|
|
Term
| When do gonads stop being indifferent? |
|
Definition
|
|
Term
| What forms at 4 weeks of gonadal development? |
|
Definition
| Wolffian duct and genital ridge |
|
|
Term
| What forms at 6 weeks of gonadal development? |
|
Definition
| primitive sex cords at genital ridge; ridge is covered in coelomic epithelium |
|
|
Term
| What forms at 8 weeks of male gonadal development? |
|
Definition
| testes form, primitive sex cords become testis cords |
|
|
Term
| What occurs at 18 weeks of male gonadal development? |
|
Definition
| Wolffian duct becomes part of vas deferens |
|
|
Term
| What occurs at 18 weeks of female gonadal development? |
|
Definition
| surface epithelium of genital ridge remains; Wolffian duct degenerates; Mullerian duct becomes Fallopian tube |
|
|
Term
| What does the expression of SRY gene trigger? |
|
Definition
|
|
Term
| What cells are testes made of? |
|
Definition
|
|
Term
| What do Leydig cells release and what happens to it? |
|
Definition
| release testosterone, which is reduced to dihydrotestosterone, triggering formation of male external genitalia |
|
|
Term
| What do Sertoli cells release and what does it do? |
|
Definition
| release anti-Mullerian duct hormone that degrades Mullerian duct |
|
|
Term
| What does testosterone cause to develop? |
|
Definition
| secondary male characteristics from |
|
|
Term
| What does the absence of SRY gene trigger? |
|
Definition
|
|
Term
| What cells are ovaries made of? |
|
Definition
| thecal and granulosa cells |
|
|
Term
| What do thecal cells release and what happens to it? |
|
Definition
| testosterone that is altered to estrogen |
|
|
Term
| What do granulosa cells release and what happens to it? |
|
Definition
| aromatase that is altered to estrogen |
|
|
Term
| What structures does estrogen activate the formation of? |
|
Definition
| secondary female characteristics, oviduct, uterus, upper vagina |
|
|
Term
| What happens when an XY individual is insensitive to testosterone? |
|
Definition
| Develop mostly female, but retain internal testicles |
|
|
Term
| What does the germ plasm contain? |
|
Definition
| RNA helicases and mitochondria |
|
|
Term
| Where do P granules localize? |
|
Definition
| posterior end; germ line precursor cells |
|
|
Term
| Where do PIE-1 proteins localize? |
|
Definition
| posterior end; germ line precursor cells |
|
|
Term
| What is required for P granules and PIE-1 proteins to localize? |
|
Definition
|
|
Term
| Do par genes have maternal or zygotic mutational effects? |
|
Definition
|
|
Term
| What do P granules contain? |
|
Definition
| contain translation regulators to specify germ cells |
|
|
Term
| What effects do PIE-1 proteins have on germline precursor cells? |
|
Definition
| repress transcripts associated with somatic cells, keeping the cell undifferentiated |
|
|
Term
| What happens when polar plasm is transplanted into sterile embryo? |
|
Definition
|
|
Term
| What are Oskar and Stauffen proteins involved in? |
|
Definition
| recruitment of germ plasm |
|
|
Term
| What happens when oskar gene is genetically engineered with a bicoid gene region in 3' UTR? |
|
Definition
| causes oskar mRNA to localize to anterior region instead of posterior; oskar will recruit germ plasm at both ends; oskar localization is sufficient for recruitment of germ plasm |
|
|
Term
| What is the order of early development in C. elegans? |
|
Definition
polarity in 1-celled zygote arises after sperm penetration
cleavage patterns
different germ layers form
axis specification occurs
gastrulation occurs |
|
|
Term
| Describe the differentiation that leads to formation of mesoderm and endoderm precursor cells. |
|
Definition
P0 diferentiates to form EMS and P1 (germ cell precursor)
EMS divides to form MS and E cells |
|
|
Term
| What end does sperm entry determine? |
|
Definition
|
|
Term
| What are the functions of PAR 3 & 6? |
|
Definition
| localize to anterior and required for formation of germ line; recruits MEX=5 |
|
|
Term
| Where does PAR 2 localize? |
|
Definition
|
|
Term
|
Definition
| promote accumulation of specific mRNAs and proteins |
|
|
Term
| What cytoskeletal system is responsible for organization of one-cell zygote? |
|
Definition
|
|
Term
| What are the functions of MEX-5? and where is it? |
|
Definition
| anterior end; inhibits translation of SKN-1 and PIE-1 to prevent initiation of transcription that would cause further differentiation |
|
|
Term
| What does PIE-1 do in P2? |
|
Definition
|
|
Term
| Where is SKN-1 active? What does SKN-1 do? |
|
Definition
| in EMS cell; activates transcription of MED genes that allow for differentiation of MS and E cells |
|
|
Term
| How does P2 induce EMS to produce an E daughter cell? |
|
Definition
| Releases MOM-2 Wnt ligand that is received by adjacent EMS cell Frizzled receptor MOM-5, triggering E cell formation |
|
|
Term
| What happens when MOM-5 is mutated? |
|
Definition
| The EMS cell cannot receive MOM-2 Wnt ligand, and two MS cells will form |
|
|
Term
| What happens when MOM-2 is mutated? |
|
Definition
| The P2 cell cannot release MOM-2 Wnt ligand, so two MS cells will form |
|
|
Term
| What type of cell movement is responsible for internalizing E and MS precursors? |
|
Definition
| ingression; contraction of outer surfaces allowing them to enter; actin and myosin likely involved |
|
|
Term
| What type of cell movement is responsible for ventral enclosure of C. elegans? What molecule is required? |
|
Definition
|
|
Term
| What is unique about early mitosis in Drosophila? |
|
Definition
| DNA replication occurs without cell division |
|
|
Term
|
Definition
| group of nuclei in common cytoplasm |
|
|
Term
| What are the implications of the formation of a syncytium in Drosophila? |
|
Definition
| molecules simply diffuse in gradients and don't have to be diffused across membranes of separate cells |
|
|
Term
|
Definition
| structures of exoskeleton of Drosophila embryo |
|
|
Term
| What do bicoid, nanos, and torso mutants do phenotypically that can be observed in Drosophila embryos? |
|
Definition
| denticle band patterning is messed up |
|
|
Term
| Provide evidence that posterior cytoplasm is sufficient for specification of posterior end. |
|
Definition
| Transplantation of posterior cytoplasm to anterior end with cause two posterior ends to develop |
|
|
Term
| What are the maternal effect genes are responsible for polarization of Drosophila zyogote? |
|
Definition
| bicoid, nanos, torso, oskar, hunchback, caudal |
|
|
Term
| Where does bicoid localize? |
|
Definition
|
|
Term
| Where does nanos localize? |
|
Definition
|
|
Term
|
Definition
| terminal (head and tail tips) of embryo |
|
|
Term
| Were are maternal mRNAs provided from to oocyte of Drosophila? |
|
Definition
| nurse cells via cytoplasmic bridges |
|
|
Term
| Where does kinesin carry mRNAs to in Drosophila? |
|
Definition
| towards positive, posterior end |
|
|
Term
| Where does dynein carry mRNAs to in Drosophila? |
|
Definition
| towards negative, anterior end |
|
|
Term
| Where does oskar localize? |
|
Definition
|
|
Term
| What does Oskar protein act as a scaffold for? |
|
Definition
|
|
Term
| What does Bicoid protein do? |
|
Definition
| acts as TF that activates trasncription of hunchback and RNA binding protein that prevents translation of caudal in anterior |
|
|
Term
| Where is Bicoid protein localized? |
|
Definition
| a gradient; most concentrated at anterior end |
|
|
Term
| Where is Nanos protein localized? |
|
Definition
| a gradient; most concentrated at posterior end |
|
|
Term
| What does Nanos protein do? |
|
Definition
| translational inhibitor of maternal hunchback mRNA in posterior |
|
|
Term
| What does Caudal protein do? |
|
Definition
| initiates posterior gene transcription in posterior end |
|
|
Term
|
Definition
|
|
Term
| What are pair rule genes? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Where are gap genes expressed? |
|
Definition
| wide, slightly overlapping regions in early embryo |
|
|
Term
| What happens when gap gene is mutated? |
|
Definition
| region where it normally acts is missing |
|
|
Term
| How is gap gene expression regulated? |
|
Definition
| mutual repression of each other |
|
|
Term
| Where are pair rule genes expressed? |
|
Definition
| in stripes of embryo; do not overlap |
|
|
Term
| What happens when a pair-rule gene is mutated? |
|
Definition
| embryos lack portions of every other segment |
|
|
Term
| What are two examples of pair-rule genes? |
|
Definition
| fushi tarazu (ftz) and even-skipped (eve) |
|
|
Term
| What is pair-rule transcription regulated by? |
|
Definition
| Bicoid, Giant, Kruppel, Hunchback binding to activate or repress |
|
|
Term
| Where are segment polarity genes expressed? |
|
Definition
| 14 stripes; one per segment |
|
|
Term
| What happens when segment polarity gene is mutated? |
|
Definition
| a defect is present in every segment |
|
|
Term
| What dictates levels of segment polarity genes? |
|
Definition
| levels of pair-rule genes |
|
|
Term
| What is expressed when eve and ftz are absent? |
|
Definition
|
|
Term
| What is expressed when eve and ftz are high? |
|
Definition
|
|
Term
| How do specific cells of Drosophila communicate? |
|
Definition
|
|
Term
| What pathways are involved in maintaining boundaries of segment-polarity genes? |
|
Definition
| Wnt and Hedgehog pathways |
|
|
Term
| How are boundaries of segment-polarity genes maintained? |
|
Definition
wingless and engrailed expressing cells are adjacent to each other
engrailed expression triggers expression of hedgehog
hedgehog is secreted and diffuses into neighboring wingless-expressing cell
further transcription of wingless is activated
wingless is secreted to engrailed-expressing cell
loop is encouraged by beta-catenin Armadillo |
|
|
Term
| What are the two movements that occur during gastrulation in Drosophila? |
|
Definition
| ventral furrow formation and germ band extension |
|
|
Term
| What cellular movement is involved in ventral furrow formation in Drosophila? |
|
Definition
| invagination of mesoderm cells, causing anterior side to scrunch and form furrow |
|
|
Term
| What molecules does apical constriction in Drosophila require? |
|
Definition
|
|
Term
| What does germ band extension do in Drosophila? |
|
Definition
| pushes germ cells around embryo, then push them internally via convergent extension |
|
|
Term
| What molecule does germ band extension require? |
|
Definition
| myosin at cell edges that constrict into temporary multicellular rosettes |
|
|
Term
|
Definition
| transcription factors that give identities to each segment |
|
|
Term
| Examples of homeotic gene mutations. |
|
Definition
antennapedia mutants have legs where antennae are normally found
bithorax mutants have additional thoracic segment with extra pair of wings |
|
|
Term
| What layer do micromeres of sea urchin embryos form? |
|
Definition
|
|
Term
| What layer do mesomeres of sea urchin embryos form? |
|
Definition
|
|
Term
| What layer do macromeres of sea urchin embryos form? |
|
Definition
|
|
Term
| At what stage is totipotency lost in sea urchin embryos? |
|
Definition
|
|
Term
| Provide evidence that totipotency is lost in 4-celled stage of sea urchin embryos. |
|
Definition
cut cell parallel to yellow band- half with animal piece makes permanent blastula, other half gets gut, some mesoderm, some ectoderm
cut perpendicular to yellow band-two normal embryos develop |
|
|
Term
| What cells influence gut specification in sea urchins? |
|
Definition
|
|
Term
| Provide evidence that micromeres influence gut specification in sea urchins. |
|
Definition
| transplanted micromeres move to interior to form skeletal elements and induce endoderm gene expression; structures from animal pole form skeletal rods |
|
|
Term
| What molecule is involved in vegetal fate specification in sea urchins? |
|
Definition
|
|
Term
| Provide evidence that beta-catenin is involved in vegetal fate specification of sea urchins. |
|
Definition
| morpholinos to block translation of beta catenin (or overexpressed C-cadherin to soak it up); causes beta-catenin to exit nuclei and end up in cell junctions; blastula becomes permanent |
|
|
Term
| What regulates dorsal-ventral axis specification in sea urchins? |
|
Definition
| Nodal signaling; a TGF-beta protein |
|
|
Term
| Where is Nodal protein localized in sea urchins? |
|
Definition
| ventral side where oral part is located |
|
|
Term
| What does Nodal protein accomplish? |
|
Definition
|
|
Term
| What type of cells make up progeny of micromeres in sea urchins? |
|
Definition
|
|
Term
| What do primary mesenchyme cells do? |
|
Definition
| cause initial invagination of archenteron |
|
|
Term
| What do secondary mesenchyme cells do? |
|
Definition
| send out filopodia into blastocoel to secrete spicules that attach to opposite end, causing elongation (convergent extension) of archenteron |
|
|
Term
| What cells will 16-cell micromere adhere to? |
|
Definition
| non-skeletogenic cells and hyaline layer |
|
|
Term
| What cells will primary mesenchyme cells adhere to? |
|
Definition
|
|
Term
| What initiates formation of archenteron? |
|
Definition
|
|
Term
| What happens when secondary mesenchyme cells are destroyed by laser ablation? |
|
Definition
| the archenteron will only elongate to 2/3 its normal elongation |
|
|
Term
| What happens if secondary mesenchyme cells attach to hyaline layer of ECM? |
|
Definition
| elongation of archenteron won't occur |
|
|
Term
| What happens if cross-linking of basal lamina in ECM is disrupted? |
|
Definition
| becomes rigid; archenteron elongation won't occur |
|
|
Term
| What effect does the introduction of NiCl2 have on sea urchin embryos? |
|
Definition
| causes radialization and disrupts primary mesenchyme cell patterning |
|
|
Term
| What happens if embryo is elongated before archenteron elongation occurs? |
|
Definition
| secondary mesenchyme cells cannot attach to opposite end, so elongation of archenteron won't occur |
|
|
