title: CTCF-promoted RNA polymerase II pausing links DNA methylation to splicing.
abstract: Alternative splicing of pre-messenger RNA is a key feature of transcriptome expansion in eukaryotic cells, yet its regulation is poorly understood. Spliceosome assembly occurs co-transcriptionally, raising the possibility that DNA structure may directly influence alternative splicing. Supporting such an association, recent reports have identified distinct histone methylation patterns, elevated nucleosome occupancy and enriched DNA methylation at exons relative to introns. Moreover, the rate of transcription elongation has been linked to alternative splicing. Here we provide the first evidence that a DNA-binding protein, CCCTC-binding factor (CTCF), can promote inclusion of weak upstream exons by mediating local RNA polymerase II pausing both in a mammalian model system for alternative splicing, CD45, and genome-wide. We further show that CTCF binding to CD45 exon 5 is inhibited by DNA methylation, leading to reciprocal effects on exon 5 inclusion. These findings provide a mechanistic basis for developmental regulation of splicing outcome through heritable epigenetic marks.
authors.affiliation: Center for Cancer Research, Mouse Cancer Genetics Program, National Cancer Institute at Frederick, Frederick, Maryland 21702, USA.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Shukla
authors.forename: Ersen
authors.initials: E
authors.lastname: Kavak
authors.forename: Melissa
authors.initials: M
authors.lastname: Gregory
authors.forename: Masahiko
authors.initials: M
authors.lastname: Imashimizu
authors.forename: Bojan
authors.initials: B
authors.lastname: Shutinoski
authors.forename: Mikhail
authors.initials: M
authors.lastname: Kashlev
authors.forename: Philipp
authors.initials: P
authors.lastname: Oberdoerffer
authors.forename: Rickard
authors.initials: R
authors.lastname: Sandberg
authors.forename: Shalini
authors.initials: S
authors.lastname: Oberdoerffer
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D000076246:CCCTC-Binding Factor; D002460:Cell Line; D002478:Cells, Cultured; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005091:Exons / Q000235:genetics; D015894:Genome, Human / Q000235:genetics; D006801:Humans; D017493:Leukocyte Common Antigens / Q000235:genetics; D051379:Mice; D011485:Protein Binding; D012319:RNA Polymerase II / Q000378:metabolism*; D022821:RNA Splice Sites / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D000076246:CCCTC-Binding Factor; C000619697:CTCF protein, human; C000619698:Ctcf protein, mouse; D022821:RNA Splice Sites; D012333:RNA, Messenger; D012097:Repressor Proteins; D012319:RNA Polymerase II; D017493:Leukocyte Common Antigens