title: Human TREX component Thoc5 affects alternative polyadenylation site choice by recruiting mammalian cleavage factor I.
abstract: The transcription-export complex (TREX) couples mRNA transcription, processing and nuclear export. We found that CFIm68, a large subunit of a heterotetrameric protein complex mammalian cleavage factor I (CFIm), which is implicated in alternative polyadenylation site choice, co-purified with Thoc5, a component of human TREX. Immunoprecipitation using antibodies against different components of TREX indicated that most likely both complexes interact via an interaction between Thoc5 and CFIm68. Microarray analysis using human HeLa cells revealed that a subset of genes was differentially expressed on Thoc5 knockdown. Notably, the depletion of Thoc5 selectively attenuated the expression of mRNAs polyadenylated at distal, but not proximal, polyadenylation sites, which phenocopied the depletion of CFIm68. Chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) indicated that CFIm68 preferentially associated with the 5' regions of genes; strikingly, the 5' peak of CFIm68 was significantly and globally reduced on Thoc5 knockdown. We suggest a model in which human Thoc5 controls polyadenylation site choice through the co-transcriptional loading of CFIm68 onto target genes.
authors.affiliation: Biomolecular Networks Laboratories, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan. katahira@anat3.med.osaka-u.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Katahira
authors.forename: Daisuke
authors.initials: D
authors.lastname: Okuzaki
authors.forename: Hitomi
authors.initials: H
authors.lastname: Inoue
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yoneda
authors.forename: Kazumitsu
authors.initials: K
authors.lastname: Maehara
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ohkawa
mesh_terms: D024506:5' Flanking Region; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D026723:Polyadenylation; D039221:mRNA Cleavage and Polyadenylation Factors / Q000378:metabolism*
chemical_list: D009687:Nuclear Proteins; C530378:THOC5 protein, human; C450562:cleavage factor Im, human; D039221:mRNA Cleavage and Polyadenylation Factors