Transcription and RNA Flashcards Preview

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Flashcards in Transcription and RNA Deck (44):
1

Changes in gene expression

- response of cells due to environmental changes
- regulation of cell cycle
- distinct activities of multitude of differentiated cell types.
- cell differentiation and development

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Promoters

DNA sequence to initiate and regulate the rate of transcription of a gene

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RNA polymerase

enzyme, synthesis of RNA from DNA template

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Differences of eukaryotes to pro (gene expression)

- chromatin
-Compartmentalization in nucleus
- Extensive RNA processing
RNA polymerase 1-3

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mRNA

template for protein synthesis,
uses polymerase II

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rRNA

component of ribosomes, uses polymerase I

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tRNA

serve as adaptor molecules that align amino acids along the mRNA template. uses polymerase III

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DNA sequence element

denotes a specific short sequence of DNA base pairs within a gene promoter

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Cis-acting DNA sequences (promoter)

Regions of non coding DNA that regulates expression of genes

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Basal or core promoter

genes transcribed by RNA polymerase II that includes TATA box and an initiator DNA sequence.

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Upstream promoter and enhancers

transcriptional regulatory sequences located at sig. distance from promoter. impacts when and how much trancsctiption will occur

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Transcription factors

proteins required to for RNA polymerase to initiate transcription.

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reporter gene (adjacent to regulatory sequence)

reports on the activity of gene regulatory sequence or promoter

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Position of enhancer

functions in any orientation or position relative to the promoter

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Initiation

process leading to RNA polymerase II beginning to synthesize mRNA

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Elongation

process of synthesizing a mRNA complementary to the coding strand of the DNA

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General transcription factors

initiate transcription but does not allow for much transcription to occur

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Gene specific factors

reponsible for regulating transcription rate of basal transcription complex

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DNA methylation

one of the two parental alleles of genes is expressed during embryotic development

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Pre-mRNA

primary transcript that is processed to form mRNA

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Processing of mRNA

Capping
polyadenylation
splicing

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7 methylguanosine cap

added to pre-mRNA, at 5'end of transcript.

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Polyadenylation

process of adding a poly-Adenine tail to pre-mRNA. AAUAA (polyadenylation signal on mRNA)

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Splicing

process of removing introns

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Spliceosomes

large complexes composed of proteins and RNAs.

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Small nuclear ribonucleoprotein particles

complexes of snnRNAs with proteins that play central roles in splicing

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Small nuclear ribonucleoprotein Adenine

form the RNA component of spliceosomes.range in size from 50 to 200

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Alternative splicing

process of varying pattern of pre- mRNA splicing . creates multiple different, but related, proteins fro the same gene

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SR slicing factos

dictate where splicesome (U1) will form to exon sequences

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Dscam

cell surface adhesion molecule important in allowing neurons to find target cells

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fundamental activity of upstream promoter elements (enhancers)

binding sites for the gene specific transcription factors that modulate activity for basal transcription complex

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transcriptional symphony

combination of transcription factors interacting at a specfiic genes promoter/enhancer sequences at any one point in time

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Steroid Hormone receptors

contain zinc finger domains. Transcription factors that regulate gene transcription in response to hormones

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homodeomain proteins

contain helix turn helix. play critical roles in the regulation of gene expression during embryonic development

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Transcriptional activators

- interact with mediators and general transcription factors
- interact coactivators, which modify chromatin structure

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Transcriptional repressors

- blocks binding of activator to DNA sequence element

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Mediator

large protein complex that binds to reinitiation complex and plays key role in liking general transcription factors to the gene-specific transcription factors that regulate gene expression

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DNA looping

allows transcription factors bound to an enhancer interact with proteins in RNA polymerase at core promoter

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Elongation

release of RNA polymerase from basal complex to initiate transcription

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Chromatin remodeling

moving, removal, and/or addition of histones

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Histone code

- histone tail acetylation and deacetylation
- other histone modifications

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Histone acetylation

modification of histones by addition of acetyl groups to specific lysine residue

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Histon acetylation
Coactivator

HAT, recruits acetlyate histones active chromatin. gives transcription factors more access to chromatin

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Histone aceytlation corepressor

HDAC, recruits decetylated histones, inactive chromatin. gives rise to a less- permisseable environment for transcription factors by condensing chromatin