Biology subjects

Singaravelu, G.

Publications and source records attributed to Singaravelu, G..

2 recordsLinked to original sources

bioRxiv2021

SPE-51, a sperm secreted protein with an Immunoglobulin-like domain, is required for sperm-egg fusion in C. elegans

Despite the importance of fertilization, the molecular basis of sperm-egg interaction is not well understood. In a forward genetics screen for fertility mutants in Caenorhabditis elegans we identified spe-51. Mutant worms make sperm that are unable to fertilize the oocyte but otherwise normal by all available measurements. The spe-51 gene encodes a secreted protein that includes an immunoglobulin (Ig)-like domain and a hydrophobic sequence of amino acids. The SPE-51 protein acts cell-autonomously and localizes to the surface of the spermatozoa. This is the first example of a secreted protein required for the interactions between the sperm and egg with genetic validation for a specific function in fertilization. Our analyses of these genes begin to build a paradigm for sperm-secreted or reproductive tract-secreted proteins that coat the sperm surface and influence their survival, motility, and/or the ability to fertilize the egg.

developmental biology↗

bioRxiv2021

The EGF-motif containing protein SPE-36 is a secreted protein required for sperm function at fertilization in C. elegans

The growing number of genes specifically required for fertilization suggests that there is a significant amount of molecular complexity at the sperm-egg interface. Thus, we have adopted a model of a "fertilization synapse" where specialized zones of interaction and multi-protein complexes mediate gamete interaction and fusion. The fertilization synapse is likely to be composed of both trans and cis protein-protein interactions at the surface of each gamete. Mutations in the Caenorhabditis elegans spe-36 gene result in a sperm-specific fertility defect. Surprisingly, spe-36 encodes a secreted EGF-motif containing protein that functions cell autonomously. Despite the fact that morphology and migratory behavior of spe-36 sperm are indistinguishable from wild-type sperm, spe-36 sperm make close contact with oocytes but fail to fertilize them. The genetic requirement for a secreted sperm-derived protein for fertilization is novel and represents a paradigm-shifting discovery in the molecular understanding of fertilization.

developmental biology↗