spe-43 is required for sperm activation in C. elegans

Dev Biol. 2018 Apr 15;436(2):75-83. doi: 10.1016/j.ydbio.2018.02.013. Epub 2018 Feb 22.


Successful fertilization requires that sperm are activated prior to contacting an oocyte. In C. elegans, this activation process, called spermiogenesis, transforms round immobile spermatids into motile, fertilization-competent spermatozoa. We describe the phenotypic and genetic characterization of spe-43, a new component of the spe-8 pathway, which is required for spermiogenesis in hermaphrodites; spe-43 hermaphrodites are self-sterile, while spe-43 males show wild-type fertility. When exposed to Pronase to activate sperm in vitro, spe-43 spermatids form long rigid spikes radiating outward from the cell periphery instead of forming a motile pseudopod, indicating that spermiogenesis initiates but is not completed. Using a combination of recombinant and deletion mapping and whole genome sequencing, we identified F09E8.1 as spe-43. SPE-43 is predicted to exist in two isoforms; one isoform appears to be a single-pass transmembrane protein while the other is predicted to be a secreted protein. SPE-43 can bind to other known sperm proteins, including SPE-4 and SPE-29, which are known to impact spermiogenesis. In summary, we have identified a membrane protein that is present in C. elegans sperm and is required for sperm activation via the hermaphrodite activation signal.

Keywords: C. elegans; Sperm; Sperm activation; Spermiogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / metabolism
  • Fertility / genetics
  • Male
  • Mutation
  • Phenotype
  • Polymorphism, Single Nucleotide
  • Reverse Transcriptase Polymerase Chain Reaction
  • Spermatogenesis / genetics*
  • Spermatogenesis / physiology
  • Spermatozoa / metabolism*
  • Spermatozoa / physiology
  • Whole Genome Sequencing


  • Caenorhabditis elegans Proteins