Lecture 16 Flashcards Preview

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Flashcards in Lecture 16 Deck (47):
1

Regulatory sequences (enhancers):

cis-acting elements

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A eukaryotic gene is regulated by many

regulatory elements and proteins

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Expression of genes are governed by the gene control region:

promoter and regulatory sequences

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binds to a gene's regulatory sequences to determine where and when transcription will initiate

Specific DNA binding proteins

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Specific DNA binding proteins can be either

repressors or activators

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Regulatory elements/sequences can be found -- either upstream or downstream from the promoter

tens of thousands of base pairs

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Genes are -- in the area of chromatin condensation...by histone --

Genes are inactivated in the area of chromatin condensation...by histone deacetylation

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Genes can be -- in areas where the chromatin is decondensed...histone --

Genes can be expressed in areas where the chromatin is decondensed...histone acetylation

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can bind to regulatory elements (enhancers) near or far away from the promoter region.

activators

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An activator can influence-- of chromatin to promote RNA polymerase to bind or stabilize the preinitiation complex.

decondensation

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Repressors: binds to control elements (--) to promote condensation; inhibit transcription.

silencer

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located within 100 – 200 bp upstream of the
start site; can be cell-type specific

Promoter-proximal element (PE):

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Enhancers are -- which can stimulate transcription from up to 50 kb from the start site

DNA sequences

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enhancers Can be located upstream or downstream from the start site, even within an --

intron

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enhancers are often cell-type specific
• Can increase transcription up to

1,000X

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n both prokaryotes and eukaryotes, transcriptional activators and repressors are --, composed of distinct functional domains...can function without the other

modular proteins

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Activation/repression domain: interacts with other proteins or .

another subunit of the same protein

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A specific gene is only expressed when a cell contains -- of the above regulatory proteins.

correct combination

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Eukaryotic gene regulatory proteins ofter assemble into -- on DNA

complexes

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-- lead to different complexes, which lead to different activities.

Different DNA binding sequences

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T/F: A protein can be in either an activator or repressor complex

true

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Enhancers are composed of one or more binding sites for --

regulatory proteins

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Activators interact with other proteins (i.e. co-activator or mediator complex) to bring in and stabilize transcription machinery, causing the --

intervening DNA to loop out

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-- is the molecular bridge between activators and RNA Pol II

Mediator

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Several DNA-bound activators can interact with a --

single mediator complex

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The mediator complex is a type of -- which are intermediary proteins that assist the transcription activators to stimulate initiation of transcription

co-activator

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Subunits of a mediator can bind to --, activation domain of various activator proteins, and histone acetylation activity

RNA pol II

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Transcription is controlled by a variety of -- that interact with specific DNA sequences.

regulatory proteins/transcription factors

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Whereas Mediator and general transcription factors are the same for all RNA pol II, -- relative to the promoter differs for each gene

transcribed genes, transcription regulators, and locations of their binding sites

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Patterns of -- can be inherited

DNA methylation

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methylated DNA is correlated with -- regions of the chromosomes

inactive

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The most commonly methylated sequence in DNA

CG (cytosine iss methylated)

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DNA sequences that prevent regulatory proteins from influencing distant genes

insulators

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T/F: Alternative RNA splicing can produce different forms of a protein from the same gene

true

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38,016 different proteins could be made from this particular gene-

Dscam

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The phosphorylation of -- slows down protein synthesis

eIF2

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IRES (internal ribosome entry site) provide opportunities for-- control

translation

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IRES-dependent translation bypasses the need for 5’ cap and its initiation translation factor - .

eIF4E

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The IRES-dependent mechanism seen mainly in --.

viruses

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mRNA can be

translated, stored in stress granules, degraded in P-bodies

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after gradual poly-A shortening -->

1. continued 3' to 5' degradation
2. recapping followed by rapid 5' to 3' degradtion

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-- of each mRNA is important for its half life

specific 3' UTR sequence

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competition between mRNA translation and decay because

deadenylase that shortens the poly-A tail in the 3' to 5' direction also associates with 5' cap

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mRNA degradation through microRNA (miRNA) involves

RISC

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Small Interference RNA (siRNA) can trigger destruction of complementary mRNA and
--

transcriptional silencing

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during mRNA degradation, -- in conjunction with other complements of RISC, initially associates with both strands of miRNA and then cleaves and discards one of them

argonaute

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argonaute cleaves the target mRNA, causing its --

rapid degradation