A nematode gene required for sperm vesicle fusion

J Cell Sci. 1997 May:110 ( Pt 9):1073-81. doi: 10.1242/jcs.110.9.1073.

Abstract

During maturation of spermatids to motile spermatozoa in Caenorhabditis elegans, large vesicles called membranous organelles (MOs) fuse with the spermatid plasma membrane. Mutations in the gene fer-1 cause abnormal spermatozoa in which the MOs do not fuse, although they abut the plasma membrane normally. Here we describe the fer-1 gene, which we found to be approximately 8.6 kb in length and to encode a 6.2 kb transcript whose expression is limited to the primary spermatocytes, the cells in which the MOs form. fer-1 is predicted to encode a 235 kDa protein which is highly charged except for a putative transmembrane domain near the C terminus. We identified the mutations associated with five fer-1 alleles, all of which are missense mutations causing single amino acid changes. FER-1 is not similar to any characterized proteins in sequence databases, nor does it contain known functional motifs other than the predicted transmembrane domain. The C-terminal transmembrane domain makes FER-1 resemble some viral fusion proteins, suggesting it may play a direct role in MO-plasma membrane fusion. FER-1 does show significant sequence similarity to several predicted human proteins of unknown function. Two of the identified fer-1 mutations are located in regions of similarity between FER-1 and two of these predicted proteins. This strengthens the biological significance of these similarities and suggests these regions of similarity represent functionally important domains of FER-1 and the human proteins.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans Proteins*
  • Cell Membrane / chemistry
  • Cell Membrane / physiology
  • Cloning, Molecular
  • Fertilization / physiology*
  • Gene Expression / physiology
  • Genes, Helminth / physiology
  • Genome
  • Helminth Proteins / chemistry
  • Helminth Proteins / genetics*
  • Humans
  • Male
  • Membrane Proteins*
  • Molecular Sequence Data
  • Mutation / physiology
  • RNA, Messenger / genetics
  • Spermatogenesis / physiology
  • Spermatozoa / physiology*
  • Spermatozoa / ultrastructure*
  • Testis / chemistry
  • Testis / physiology

Substances

  • Caenorhabditis elegans Proteins
  • FER-1 protein, C elegans
  • Helminth Proteins
  • Membrane Proteins
  • RNA, Messenger

Associated data

  • GENBANK/U57652
  • GENBANK/Z79755