MMG exam 1 - Transcription (E. Coli Pol) o (-) is upstream...

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Transcription (E. Coli Pol) o (-) is upstream (+) is downstream o Sigma binds to promoter at -10, -35; after 10 bases leaves Re-Mit-Tance (1, 2, 3) rRNA, mRNA, tRNA RNA synthesis RNA poly 5’-triphosphates (NTPs) Doesn’t require primer Alpha identifies correct sites for initiation DNA sequence that RNA binds Promoter (+1 position) o Initiated by binding 2 NTPs o Poly A tail facilitates dissociation of RNA from template Cis-acting control elements regulatory sequence like operator Trans-acting control elements repressors…(affect different chromosomes) RNA Pol I 2 largest rRNA 28s, 18s, 5.8s o Pol I and TFs at initiation site of rRNA transcription o SL1 (TBP) required RNA Pol II mRNA (require TFs, TATA box) o 1) site specific activating proteins that find enhancer DNA regions o 2) common promoter-recognition complex, TFIID o 3) holoenzyme that binds the Inr DNA site o TFIID, then TFIIB, Pol attches, then F, E, H-core promoter o Dumb blonde fuck everyone hard RNA Pol III tRNA, 5s rRNA Transcription complex o TFIID to promoter: TBP + TBP-associated factors (TAFs) + TFIIB, F, E, H Gene expression regulated by repressors and transcription activators Elongation factors P C-term of RNA Pol II MicroRNA short non-coding function as regulators of gene expression tRNA CCA at 3’ end, site of AA attachment pre-mRNA is initial product of transcription C-term domain (CTD) of RNA Pol II mRNA processing o 1) Modification of 5’ by addition of M-cap o 2) Poly-A tail o 3) termination Export is independent of Ran-GTP, requires TAP Pre-mRNA splicing o 1) Cleaved at 5’ splice site and 5’ end of intron joined to adenine within intron o 2) Simultaneous cleavage at 3’, ligation of 2 exons 3 critical sequence elements of pre-mRNA o 1) sequence at 5’ splice o 2) sequence at 3’ splice o 3) sequence within intron at branch point Spliceosomes (splice takes place in) o snRNA forms snRNPs
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o U1 snRNP binds to 5’ splice site; U2 binds at branch o Self-slicing 1) cleavage 5’ mediated by guanosine cofactor 2) attack by adenosine nucleotide in intron Alternative splicing exons in varied combo control gene by generating multiple mRNA by single template RNA-editing processing events (not splicing) that alter protein-coding sequence (single) Introns degraded within nucleus via enzyme unique 2’-5’ bond at branch Nonsense-mediated mRNA decay degradation of mRNA that lack complete open-reading frame Cytoplasmic degradation initiated by shortening poly-A tail then removal of 5’ cap Transcription o RNA Pol methyl cap on 5’ mRNA + cleavage factors + stability factors Poly A polymerase cleaves 3’ + A residues proteins bind to tail increases growth rate splicing RNA Pol II pre-mRNA processing mRNA nucleus to cyto and translated Long dsRNA enter cell cleaved by Dicer (RNA Pol III)
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MMG exam 1 - Transcription (E. Coli Pol) o (-) is upstream...

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