Flashcards in 4 RNA Synthesis Deck (25):
what does RNA pol 1 transcribe?
what does RNA pol 2 trasncribe?
pre-mRNA (heterogenous nuclear RNA)
what does RNA pol3 trans?
tRNA, 5s rRNA and other small RNA genes
the different RNA polymerases can be distinguished from one another by their sensitivity to what?
in the transcription of rRNA, what promotes the binding of RNA pol1 to the regulatory region
Factor B and Factor S proteins
in the trans of 5S rRNA, what proteins allow RNA pol 3 to begin transcribing?
TF3A and TF3C bind the promoter which permits recruitment of TF3B and finally pol3
where are the promoters for RNA pol3 typically found?
within the gene
what are enhancers?
DNA sequences taht can up regulate transcription of neighboring genes
-located upstream, downstream, or within a gene
What is the purpose of a TATAA box?
this is the site where the polymerase binds and being transcribing.
name the order of proteins recruited to the TATAA box?
what is this group of proteins called?
4. TF2E and RNA pol2 silmultaneously
-basal transcription factors (required for all genes)
what are the three major steps in mRNA processing?
what is the 5' cap at the end of eukaryotic mRNA composed of
7 methyl guanosine
after a gene is transcribed, what happens at the 3' end of mRNA?
a poly A tail is added
what sequence is found 10 to 30 nt up from the poly A tail?
what is recognized by the cleavage and poly-adenylation specificity factor (CPSF)?
are introns or exons found in mature mRNA
what is the stepwise process of mRNA splicing?
1. cleavage at 5' exon intron junction and formation of a lariat
2. circulization of intron and nucleophilic attack
3. cleavage of 3' intron exon junction and ligation of neighboring exons
where does splicing take place?
spliceosomes, large ribonucleotide protein particles akin to ribosomes
what type of RNA do ribosomes contain?
small nuclear RNA (SNRNA's) U1, 2, 4, 5, 6
in general, what is a thalassemia?
abnormalitys of Hb proteins, mainly a deficiency in one of the subtypes
what is the correlate between splicing and thalassemia?
1/4 of all mutations in the globin gene are in regions that specify correct splicing
what is alternative splicing?
ways to splice a common transcript in a way that it produces multiple unique protein products. this is found in different cell types
what is rifampacin?
blocks initiation of bacterial RNA synthesis
what is actinomycin?
binds to double helical DNA and prevents it from being transcribed