Term
| Six Ways to regulate gene expression in eukaryotes? |
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Definition
1)Transcriptional control: when and how often a gene is transcribed
2) RNA processing control: controlling the splicing and processing of RNA transcripts
3)RNA transport and localization: controlling which mRNAs are transported out of the nucleus and where they go in the cytoplasm
4)Translational control: selecting which mRNAs are translated
5) mRNA degradation control: selectively destabilizing certain mRNAs in the cytoplasm
6) Protein activity control: selectively activating, deactivating, or locating specific protein molecules after they have been made.
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Term
| Function of the site-specific gene regulatory proteins? |
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Definition
•Accelerate the rate of transcription initiation
•RECRUIT RNA Pol II (formation of the PIC)
-via recruitment of GTFs
•Recruit chromatin remodeling machinery
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Term
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Four important aspects of
eukaryotic gene regulation
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Definition
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1.Access to eukaryotic promoters is restricted by chromatin.
Activation of transcription is associated with local changes
in chromatin structure.
2.Positive mechanisms predominate-virtually all Euk genes
require activation to be transcribed.
3.Large, multimeric complexes regulate transcription
4.Transcription is separated in both space and time from translation
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Term
Prokaryotic transcription
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Definition
•Can have multiple genes regulated by one operon
•RNA Pol always has some access to DNA
•RNA polymerase requires one general transcription factor
•Transcription is not separated from translation
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Term
| Similarities in eukaryotic and bacterial gene expression? |
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Definition
•Requirement for gene regulatory proteins (transregulators)
-transcription factors or transactivators
•Requirement for Cis acting sequences
-bacteria: operons
-eukaryotes; proximal promoters and distal regulatory sequences
•Importance of weak and reversible protein-protein interactions
•Versatility afforded by DNA looping
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Term
| HATs -histone acetyl transferases? |
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Definition
-remodel via acetylation of histones
-facilitate loading of activators onto nucleosome templates
-initiate localized remodeling of chromatin around target genes
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Term
| Acetylation of histone tails in the nucleosome core affects..... |
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Definition
| the core’s affinity for DNA! |
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Term
Characteristics of eukaryotic gene regulatory regions |
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Definition
- TATA: -25 - -35 bp upstream of start (promoter)
- Regulatory sequence: cis sequence (where site specific gene regulatory proteins bind (transcription factor binding site)
- Distance from promoter region to upstream regulatory sequence depends on gene
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Term
Changes in Chromatin during/ before gene transcription
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Definition
- Before transcription chromatin is tightly bound (heterochromatin)
- Transcriptionally active Chromatin is DNAse sensitive
- During transcription chromatin is loosely bound (euchromatin)
- 4 ways to alter chromatin structure
o via chromatin remodeling complex
o histone removal
o histone replacement
o histone modifying enzyme
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