Term
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Definition
| the less condensed chromatin |
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Term
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Definition
| the transcription-associated structural changes in chromatin |
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Term
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Definition
| found in all eukaryotic cells & contain at least six core polypeptides that together remodel chromatin so that nucleosomes become more irregularly spaced |
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Term
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Definition
| remodels chromatin in ways that complement & overlap the activity of SWI/SNF |
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Term
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Definition
| a family of ATP-dependent remodeling enzymes |
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Term
| histone acetyltransferases (HATs) |
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Definition
| enzymes that acetylate particular Lys residues |
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Term
| histone deacetylases (HDACs) |
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Definition
| reduces the activity of acetylation of nucleosomes when transcription of a gene is no longer required; works as part of a general gene-silencing process that restores the chromatin to a transcriptionally inactive state |
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Term
| What is the relationship between enhancers & upstream activator sequences (UASs)? |
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Definition
| The additional regulatory sequences, generally bound by transcription activators, are usually called ENHANCERS in higher eukaryotes & UASs in yeast |
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Term
| 5 types of proteins whose binding is required for successful binding of active RNA polymerase II holoenzyme at one of its promoters |
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Definition
1. transcription activators
2. architectural regulators
3. chromatin modification & remodeling proteins
4. coactivators
5. basal transcription factors |
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Term
| high mobility group (HMG) |
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Definition
| play an important structural role in chromatin remodeling & transcriptional activation |
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Term
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Definition
| a major eukaryotic coactivator consisting of 20 to 30 or more polypeptides in a protein complex |
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Term
| What is the relationship between preinitiation complex (PIC) & TATA-binding protein (TBP)? |
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Definition
| The first component to bind in the assembly of a PIC at the TATA box of a typical Pol II promoter is the TBP |
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Term
| hormone response elements (HREs) |
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Definition
| a highly specific DNA sequence to which the hormone-receptor complex binds in order to act; alters gene expression |
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Term
| steroid receptor RNA activator (SRA) |
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Definition
| a coactivator with which hormone receptors activate transcription; an ~700 nucleotide RNA |
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Term
| CRE-binding protein (CREB) |
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Definition
| a nuclear protein that is phosphorylated by the catalytic subunit of protein kinase A |
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Term
| 4 main mechanisms of translational regulation in eukaryotes |
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Definition
1. translation initiation factors are subject to phosphorylation by protein kinases
2. some proteins bind directly to mRNA & act as translational repressors, many of them binding at specific sites in the 3' untranslated region
3. binding proteins, present in eukaryotes form yeast to mammals, disrupt the interaction eIF4E & eIF4G
4. RNA-mediated regulation of gene expression often occurs at the level of translational repression |
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Term
| HCR (hemin-controlled repressor) |
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Definition
| a protein kinase; gets activated to catalyze the phosphorylation of eIF2 |
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Term
| small temporal RNAs (stRNAs) |
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Definition
| the many miRNAs that are present only transiently during development |
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Term
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Definition
| all RNAs that do not encode proteins (including rRNAs & tRNAs) |
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Term
| constitutive gene expression |
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Definition
| unvarying expression of a gene |
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Term
| regulated gene expression |
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Definition
| for gene products whose cellular levels rise & fall in response to molecular signals |
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Term
| What is the relationship between inducible & induction? |
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Definition
| Gene products that increase in concentration under particular molecular circumstances are referred to as INDUCIBLE; the process of increasing their expression is INDUCTION |
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Term
| What is the relationship between repressible & repression? |
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Definition
| Gene products that decrease in concentration in response to a molecular signal are referred to as REPRESSIBLE, and the process is called REPRESSION |
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Term
| 3 types of proteins that regulate transcription initiation by RNA polymerase |
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Definition
1. specificity factors
2. repressors
3. activators |
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Term
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Definition
| regulation by means of a repressor protein that blocks transcription |
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Term
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Definition
| a molecular signal which regulates repressor binding to DNA; usually is a small molecule or a protein that binds to the repressor & causes a conformational change |
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Term
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Definition
| activators provide a molecular counterpoint to repressors by binding to DNA & enhancing the activity of RNA polymerase at a promoter |
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Term
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Definition
| proteins that facilitate looping; bind to intervening sites & facilitate the looping of DNA |
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Term
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Definition
| the gene cluster & promoter plus additional sequences that function together in regulation |
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Term
| 2 DNA-binding motifs that play prominent roles in the binding of DNA by regulatory proteins |
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Definition
1. helix-turn-helix
2. zinc finger |
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Term
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Definition
| the phenomenon through which appropriate regulation of different genes is accomplished by utilizing different combinations of a limited repertoire of transcription factors at each gene |
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