title: The Caenorhabditis elegans histone hairpin-binding protein is required for core histone gene expression and is essential for embryonic and postembryonic cell division.
abstract: As in all metazoans, the replication-dependent histone genes of Caenorhabditis elegans lack introns and contain a short hairpin structure in the 3' untranslated region. This hairpin structure is a key element for post-transcriptional regulation of histone gene expression and determines mRNA 3' end formation, nuclear export, translation and mRNA decay. All these steps contribute to the S-phase-specific expression of the replication-dependent histone genes. The hairpin structure is the binding site for histone hairpin-binding protein that is required for hairpin-dependent regulation. Here, we demonstrate that the C. elegans histone hairpin-binding protein gene is transcribed in dividing cells during embryogenesis and postembryonic development. Depletion of histone hairpin-binding protein (HBP) function in early embryos using RNA-mediated interference leads to an embryonic-lethal phenotype brought about by defects in chromosome condensation. A similar phenotype was obtained by depleting histones H3 and H4 in early embryos, indicating that the defects in hairpin-binding protein-depleted embryos are caused by reduced histone biosynthesis. We have confirmed this by showing that HBP depletion reduces histone gene expression. Depletion of HBP during postembryonic development also results in defects in cell division during late larval development. In addition, we have observed defects in the specification of vulval cell fate in animals depleted for histone H3 and H4, which indicates that histone proteins are required for cell fate regulation during vulval development.
authors.affiliation: Department of Molecular and Cell Biology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Pettitt
authors.forename: Catriona
authors.initials: C
authors.lastname: Crombie
authors.forename: Daniel
authors.initials: D
authors.lastname: Schümperli
authors.forename: Berndt
authors.initials: B
authors.lastname: Müller
mesh_terms: D020413:3' Untranslated Regions / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000502:physiology*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002455:Cell Division; D002868:Chromosomal Proteins, Non-Histone; D017124:Conserved Sequence; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007814:Larva / Q000648:ultrastructure; D008164:Luminescent Proteins / Q000032:analysis; D008969:Molecular Sequence Data; D018510:RNA, Helminth / Q000032:analysis; D016601:RNA-Binding Proteins; D016196:S Phase
chemical_list: D020413:3' Untranslated Regions; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D008164:Luminescent Proteins; D018510:RNA, Helminth; D016601:RNA-Binding Proteins; C458499:cdl-1 protein, C elegans; D049452:Green Fluorescent Proteins