BIO 319 Lecture 31: Translation in Eukaryotes
18 Dec 2018
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Document Summary
Shine-dalgarno sequence is complementary to a pyrimidine rich region on the 16s rrna component of the 30s subunit. Translation initiation: eif4, a multiprotein complex that recognizes the 7- methylguanosine cap at the 5" end of the mrna then facilitates the binding of the 5" end to the. Consensus sequence around the aug determines whether or not it is selected as a start codon. When polyadenylation signal sequence (aauaaa) is present an endonuclease cleavage occurs about 20 nt downstream from this sequence and the poly a-polymerase adds adenine nucleotides to the 3" end without being degraded. Bound by a poly-a binding protein in the cytoplasm (pab1) De-adenylation (tail shortening) can trigger rapid degradation of the rna. Most rna degradation occur from 3" to 5" end. As mrna ages the poly- a tail becomes shorter. The longer the poly-a tail, the longer the mrna can stay in the cytoplasm. Have translation initiation factors that tag rna to be translated.
