Transcription Flashcards
DNA’s code is copied and taken to the
cytosol
after transcription, mRNA without modification is just a
primary transcript
what will happen to a primary transcript that goes outside the nucleus?
destroyed
process of copying the sequence of one strand of DNA
transcription
key factors of transcription:
[PERT]
Promoter and its key element
- TATA box
Enhancers and Silencers
RNA Polymerase II
Transcription factors
- for recruitment of RNA polymerase
catalyzes the formation of rRNA
Polymerase i
catalyzes the formation of mRNA
Polymerase II
catalyzes the formation of tRNA
Polymerase III
tells the RNA polymerase where to attach and begin transcription
promoter
region on DNA where RNA polymerase must begin the transcription of RNA
promoter
TATA box (hogness box) is located here
promoter
contain information for transcription initiation; major site for controlling of gene expression
promoter
promoters are found before the transcriptional start site, approximately how many nucleotides?
25
true or false. TATA-less promoters cannot control transcription
false
what are the elements of TATA-less promoters
Inr (initiator element)
DPE (downstream promoter element)
found 1 nucleotide before the transcription site
Inr
found 28 or 34+ nucleotides before the transcription site
DPE
TCA (G/C) T (T/C)
Inr
(A/G) G (A/T) CGTG
DPE
forms an apparatus that binds DNA and initiates transcription
transcription factors
activated by signals from outside the cell such as hormones and growth factors
transcription factors
sets the stage for transcription by forming a pocking or RNA polymerase
transcription factors
transcription steps:
[IET]
Initiation
Elongation
Termination
binds to the TATA box and recruits other TFs
TFIID
stabilizes the TFIID
TFIIA
aids in the start site selection of RNA pol II; links the RNA pol II
TFIIB
destabilizes non-specific interactions of RNA pol II and DNA
TFIIF
RNA pol II binds in what state?
unphosphorylated state
what happens to RNA pol II once IIA, IIB, and IIF are present?
deactivated
what binds to form the pre-initiation complex (PIC)?
IIE and IIH
controls the function of IIH and enhances the melting of the promoter
IIE
as a helicase, it melts the promoter; as a kinase, it activates RNA pol II
IIH
due to TFIIH, RNA pol II is
phosphorylated
in this step, nucleotides are added
elongation
termination signal
AAUAAA
cleaves the RNA from RNA pol II
CPSF
- Cleavage and Polyadenylation Specificity Factor
RNA that is a direct copy if the DNA
primary transcript
methods to increase the stability of mRNA being exported to the cytoplasm
RNA capping
Polyadenylation
RNA capping (addition of GTP) happens at the __ end of the RNA
5’
purpose of RNA capping:
(1) protects the RNA from exonucleases
(2) allows the ribosome to recognize the beginning of mRNA
modifies the 3’ end of the primary transcript
polyadenylation
plays a role in the stability of mRNA and helps in its transport to the cytoplasm
poly(A) tail
ribonucleoproteins that form spliceosomes
snRNPs
cuts the introns and attaches the exons
spliceosome
