title: SPE-44 implements sperm cell fate.
abstract: The sperm/oocyte decision in the hermaphrodite germline of Caenorhabditis elegans provides a powerful model for the characterization of stem cell fate specification and differentiation. The germline sex determination program that governs gamete fate has been well studied, but direct mediators of cell-type-specific transcription are largely unknown. We report the identification of spe-44 as a critical regulator of sperm gene expression. Deletion of spe-44 causes sperm-specific defects in cytokinesis, cell cycle progression, and organelle assembly resulting in sterility. Expression of spe-44 correlates precisely with spermatogenesis and is regulated by the germline sex determination pathway. spe-44 is required for the appropriate expression of several hundred sperm-enriched genes. The SPE-44 protein is restricted to the sperm-producing germline, where it localizes to the autosomes (which contain sperm genes) but is excluded from the transcriptionally silent X chromosome (which does not). The orthologous gene in other Caenorhabditis species is similarly expressed in a sex-biased manner, and the protein likewise exhibits autosome-specific localization in developing sperm, strongly suggestive of an evolutionarily conserved role in sperm gene expression. Our analysis represents the first identification of a transcriptional regulator whose primary function is the control of gamete-type-specific transcription in this system.
authors.affiliation: Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America.
authors.forename: Madhura
authors.initials: M
authors.lastname: Kulkarni
authors.forename: Diane C
authors.initials: DC
authors.lastname: Shakes
authors.forename: Katie
authors.initials: K
authors.lastname: Guevel
authors.forename: Harold E
authors.initials: HE
authors.lastname: Smith
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D059447:Cell Cycle Checkpoints; D002454:Cell Differentiation; D019070:Cell Lineage; D002843:Chromatin; D048749:Cytokinesis; D018507:Gene Expression Regulation, Developmental; D008297:Male; D019849:Sex Determination Processes; D015398:Signal Transduction / Q000235:genetics*; D013091:Spermatogenesis / Q000235:genetics; D013094:Spermatozoa / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D029742:Caenorhabditis elegans Proteins; D002843:Chromatin; C575116:SPE-44 protein,C elegans