title: The proper splicing of RNAi factors is critical for pericentric heterochromatin assembly in fission yeast.
abstract: Heterochromatin preferentially assembles at repetitive DNA elements, playing roles in transcriptional silencing, recombination suppression, and chromosome segregation. The RNAi machinery is required for heterochromatin assembly in a diverse range of organisms. In fission yeast, RNA splicing factors are also required for pericentric heterochromatin assembly, and a prevailing model is that splicing factors provide a platform for siRNA generation independently of their splicing activity. Here, by screening the fission yeast deletion library, we discovered four novel splicing factors that are required for pericentric heterochromatin assembly. Sequencing total cellular RNAs from the strongest of these mutants, cwf14Δ, showed intron retention in mRNAs of several RNAi factors. Moreover, introducing cDNA versions of RNAi factors significantly restored pericentric heterochromatin in splicing mutants. We also found that mutations of splicing factors resulted in defective telomeric heterochromatin assembly and mis-splicing the mRNA of shelterin component Tpz1, and that replacement of tpz1+ with its cDNA partially rescued heterochromatin defects at telomeres in splicing mutants. Thus, proper splicing of RNAi and shelterin factors contributes to heterochromatin assembly at pericentric regions and telomeres.
authors.affiliation: Department of Biological Sciences, Columbia University, New York, New York, United States of America.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Kallgren
authors.affiliation: Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York, United States of America.
authors.forename: Stuart
authors.initials: S
authors.lastname: Andrews
authors.affiliation: Department of Biological Sciences, Columbia University, New York, New York, United States of America.
authors.forename: Xavier
authors.initials: X
authors.lastname: Tadeo
authors.affiliation: Department of Biological Sciences, Columbia University, New York, New York, United States of America.
authors.forename: Haitong
authors.initials: H
authors.lastname: Hou
authors.affiliation: Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America.
authors.forename: James J
authors.initials: JJ
authors.lastname: Moresco
authors.affiliation: Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America.
authors.forename: Patricia G
authors.initials: PG
authors.lastname: Tu
authors.affiliation: Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America.
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.affiliation: Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York, United States of America.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Nagy
authors.affiliation: Department of Biological Sciences, Columbia University, New York, New York, United States of America.
authors.forename: Songtao
authors.initials: S
authors.lastname: Jia
mesh_terms: D002352:Carrier Proteins / Q000235:genetics; D002503:Centromere / Q000235:genetics* / Q000648:ultrastructure; D020090:Chromosome Segregation / Q000235:genetics; D004268:DNA-Binding Proteins; D020868:Gene Silencing; D006570:Heterochromatin / Q000235:genetics* / Q000648:ultrastructure; D034622:RNA Interference; D012326:RNA Splicing / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D012568:Schizosaccharomyces; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics; D016615:Telomere / Q000235:genetics / Q000648:ultrastructure
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006570:Heterochromatin; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D029702:Schizosaccharomyces pombe Proteins; C529646:Tpz1 protein, S pombe