Skip to main content
. 2024 Apr 8;52(8):4483–4501. doi: 10.1093/nar/gkae240

Figure 5.

Figure 5.

Identified CPA factors implicated in pre-mRNA 3′ end processing. Eukaryotic mRNA 3′ end processing is a multi-step process (126,127). In this study, we identified a variety of CPA factors implicated in multiple steps of 3′ end processing. (i) PPP1R10/PNUTS acts as a scaffold of a PP1 phosphatase complex (128), whose dephosphorylation of the elongation factor SUPT5H is important for 3′ end processing (31). (ii) CCNK/CDK12 kinase complex is responsible for S2-phophorylation of the RNAP II CTD (106,107), which exhibits its highest phosphorylation levels at the 3′ ends of genes (109). (iii) CID containing proteins PCF11 and RPRD1B link the S2-phophorylated RNAP II CTD (94,98) to the 3′ ends of mRNA (99,100), resulting in the dislodgement of RNAP II at the 3′ ends of genes. (iv) The canonical core CPA machinery comprising CPSF, CSTF, CFI, CFII and the scaffold protein SYMPK bind to the PAS and adjacent RNA sequences (4,17). (v) CBLL1-containing MACOM synthesizes the m6A that has been implicated in 3′ end processing (32,33).