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Unformatted text preview: 91 BIO 1140 Unit 2-2: Transcription Alternative mRNA
α-tropomyosin in smooth and
striated muscle 25 Fig. 13-9, p. 293 BIO 1140 Unit 2-2: Transcription Pre-mRNA Processing
4. mRNA Capping:
A cap attached to the 5´ end of the
mRNA results in more efficient translation.
(don’t memorize the structure, just call it
a 7MeG cap). 5. Polyadenylation:
3’ to the signal AAUAAA, polyA polymerase adds ~50-250 adenine
nucleotides to form the “Poly(A) tail”
Proteins bind to the “tail” and protect mRNA from RNA-digesting enzymes 6. Nucleoside modification (Unit 1, Supplemental Info) 26 BIO 1140 Unit 2-2: Transcription Pre-mRNA Processing
7. RNA Editing:
Specific bases in the RNA are changed. Some examples are a C in the RNA becomes a uracil (U) (cytidine deaminase)
this can change a codon if in the open reading frame (ORF)
an A in the RNA becomes an inosine (I): (adenosine deaminase)
the ribosome translates I as a G thus changing a codon in the ORF. These changes can lead to changes in the protein
and its function, or splicing or may have no function at all! 27 BIO 1140 Un...
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This note was uploaded on 03/26/2014 for the course BIO 1140 taught by Professor Fenwick during the Winter '07 term at University of Ottawa.
- Winter '07