The cap binding complex influences H2B ubiquitination by facilitating splicing of the SUS1 pre-mRNA.
Pre-messenger RNA splicing is carried out by a large ribonucleoprotein complex called the spliceosome. Despite the striking evolutionary conservation of the spliceosomal components and their functions, controversy persists about the relative importance of splicing in Saccharomyces cerevisiae-particularly given the paucity of intron-containing genes in yeast. Here we show that splicing of one pre-messenger RNA, SUS1, a component of the histone H2B ubiquitin protease machinery, is essential for establishing the proper modification state of chromatin. One protein complex that is intimately involved in pre-mRNA splicing, the yeast cap-binding complex, appears to be particularly important, as evidenced by its extensive and unique genetic interactions with enzymes that catalyze histone H2B ubiquitination. Microarray studies show that cap binding complex (CBC) deletion has a global effect on gene expression, and for approximately 20% of these genes, this effect is suppressed when ubiquitination of histone H2B is eliminated. Consistent with this finding of histone H2B dependent effects on gene expression, deletion of the yeast cap binding complex leads to overubiquitination of histone H2B. A key component of the ubiquitin-protease module of the SAGA complex, Sus1, is encoded by a gene that contains two introns and is misspliced when the CBC is deleted, leading to destabilization of the ubiquitin protease complex and defective modulation of cellular H2B levels. These data demonstrate that pre-mRNA splicing plays a critical role in histone H2B ubiquitination and that the CBC in particular helps to establish the proper state of chromatin and proper expression of genes that are regulated at the level of histone H2B ubiquitination.
Hossain
Munshi Azad
MA
Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, USA.
Claggett
Julia M
JM
Nguyen
Tiffany
T
Johnson
Tracy L
TL
D001119:Arginase / Q000235:genetics; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D006657:Histones / Q000378:metabolism*; D039502:Nuclear Cap-Binding Protein Complex / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D039381:RNA Cap-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism*; D012326:RNA Splicing; D012331:RNA, Fungal / Q000235:genetics* / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D054875:Ubiquitination
C100383:CBC2 protein, S cerevisiae; D017931:DNA Primers; D006657:Histones; D039502:Nuclear Cap-Binding Protein Complex; D009687:Nuclear Proteins; D039381:RNA Cap-Binding Proteins; D012322:RNA Precursors; D012331:RNA, Fungal; D016601:RNA-Binding Proteins; C489245:SGF11 protein, S cerevisiae; C101398:STO1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C481300:Sus1 protein, S cerevisiae; D014157:Transcription Factors; C540423:ARG1 protein, S cerevisiae; D001119:Arginase