Processing of Intronless Pre-mRNAs Authored: Wahle, E, 2003-06-05 08:30:31 Edited: Gillespie, ME, 0000-00-00 00:00:00 Pubmed11909521 Reactome Database ID Release 4377595 Reactome, http://www.reactome.org ReactomeREACT_1096 The 3' ends of eukaryotic mRNAs are generated by posttranscriptional processing of an extended primary transcript. For almost all RNAs, 3' processing consists of two steps: The mRNA is first cleaved at a particular phosphodiester bond downstream of the coding sequence. The upstream fragment then receives a poly(A) tail of approximately 250 adenylate residues whereas the downstream fragment is degraded. The two partial reactions are coupled so that reaction intermediates are usually undetectable. While 3' processing can be studied as an isolated event in vitro, it appears to be connected to transcription, splicing and transcription termination in vivo. Recognition of AAUAAA sequence by CPSF Recruitment of CstF to the CPSF Bound Pre-mRNA Cleavage of Intronless Pre-mRNA at 3'-end Binding of Cleavage factors and Poly(A)Polymerase to the CstF:CPSF:Pre-mRNA Complex Cleavage and polyadenylation of Intronless Pre-mRNA PathwayStep79 PathwayStep80 PathwayStep82 PathwayStep81 PathwayStep83