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Molecular Biology of the Gene

Primary transcripts produced by RNA polymerases are generally faithful copies of the DNA template. However, most final/functional forms of these RNAs vary substantially from the primary transcript. Give as many examples as possible of different types of RNA processing. Give an example of an RNA class which is not routinely processed.

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The major processing events that happen after DNA is copied into RNA are 5' capping, 3' poly-adenylation and splicing.

1) 5' capping: the new RNA molecule is modified by addition of a "cap" that consists of a modified guanine nucleotide. The capping reaction is performed by three enzymes acting in succession: one (a phosphatase) removes one phosphate from the 5 end of the nascent RNA, another (a guanyl transferase) adds a GMP in a reverse linkage (5 to 5 instead of 5 to 3 ), and a third (a methyl transferase) adds a methyl group to the guanosine.
2) 3' poly-adenylation: Proteins assemble to perform the processing that creates the 3 end of the mRNA. ...

Solution Summary

The solution discusses the molecular biology of the gene.