RNA Processing

This chapter explores RNA processing events, which are points for regulation and quality control, and are sources of diversity. Many RNA processing reactions are directed by RNA components. Transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs) are processed out of longer precursor transcripts, and the nucleotides are post-transcriptionally modified. Meanwhile, the maturation of eukaryotic messenger RNAs (mRNAs) requires the addition of a 5' cap and a poly(A) tail—processes that are closely tied to transcription, splicing, transport out of the nucleus, and ultimately translation. The chapter then explains RNA splicing, RNA editing, and RNA degradation. RNA splicing allows the generation of great diversity in RNA products and can be catalysed by the RNA itself (self-splicing) or by a large protein and RNA-containing complex called the spliceosome. The chapter also looks at RNA-binding domains in proteins.