title: The conserved intronic cleavage and polyadenylation site of CstF-77 gene imparts control of 3' end processing activity through feedback autoregulation and by U1 snRNP.
abstract: The human gene encoding the cleavage/polyadenylation (C/P) factor CstF-77 contains 21 exons. However, intron 3 (In3) accounts for nearly half of the gene region, and contains a C/P site (pA) with medium strength, leading to short mRNA isoforms with no apparent protein products. This intron contains a weak 5' splice site (5'SS), opposite to the general trend for large introns in the human genome. Importantly, the intron size and strengths of 5'SS and pA are all highly conserved across vertebrates, and perturbation of these parameters drastically alters intronic C/P. We found that the usage of In3 pA is responsive to the expression level of CstF-77 as well as several other C/P factors, indicating it attenuates the expression of CstF-77 via a negative feedback mechanism. Significantly, intronic C/P of CstF-77 pre-mRNA correlates with global 3'UTR length across cells and tissues. In addition, inhibition of U1 snRNP also leads to regulation of the usage of In3 pA, suggesting that the C/P activity in the cell can be cross-regulated by splicing, leading to coordination between these two processes. Importantly, perturbation of CstF-77 expression leads to widespread alternative cleavage and polyadenylation (APA) and disturbance of cell proliferation and differentiation. Thus, the conserved intronic pA of the CstF-77 gene may function as a sensor for cellular C/P and splicing activities, controlling the homeostasis of CstF-77 and C/P activity and impacting cell proliferation and differentiation.
authors.affiliation: Department of Biochemistry and Molecular Biology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, USA.
authors.forename: Wenting
authors.initials: W
authors.lastname: Luo
authors.forename: Zhe
authors.initials: Z
authors.lastname: Ji
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Pan
authors.forename: Bei
authors.initials: B
authors.lastname: You
authors.forename: Mainul
authors.initials: M
authors.lastname: Hoque
authors.forename: Wencheng
authors.initials: W
authors.lastname: Li
authors.forename: Samuel I
authors.initials: SI
authors.lastname: Gunderson
authors.forename: Bin
authors.initials: B
authors.lastname: Tian
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D049109:Cell Proliferation; D039241:Cleavage Stimulation Factor / Q000235:genetics* / Q000378:metabolism; D005091:Exons / Q000235:genetics; D015894:Genome, Human; D006367:HeLa Cells; D006801:Humans; D007438:Introns / Q000235:genetics*; D026723:Polyadenylation / Q000235:genetics*; D022821:RNA Splice Sites / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000037:antagonists & inhibitors / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; C546606:CSTF3 protein, human; D039241:Cleavage Stimulation Factor; D022821:RNA Splice Sites; D012333:RNA, Messenger; D017412:Ribonucleoprotein, U1 Small Nuclear