title: Lack of Spem1 causes aberrant cytoplasm removal, sperm deformation, and male infertility.
abstract: We identified a previously uncharacterized gene, spermatid maturation 1 (Spem1), encoding a protein exclusively expressed in the cytoplasm of steps 14-16 elongated spermatids in the mouse testis. This protein contains no known functional domains and is highly conserved across mammalian species. Male mice deficient in Spem1 were completely infertile because of deformed sperm characterized by a bent head wrapped around by the neck and the middle piece of the tail. We show that lack of Spem1 causes failure of the cytoplasm to become loose and detach from the head and the neck region of the developing spermatozoa. Retained cytoplasmic components mechanically obstruct the straightening of the sperm head and the stretching of the growing tail, leading to the bending of the head in the neck, followed by the wrapping of the head by the neck or the middle piece of the sperm tail. Our study reveals that proper cytoplasm removal is a genetically regulated process requiring the participation of Spem1 and that lack of Spem1 causes sperm deformation and male infertility.
authors.affiliation: Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
authors.forename: Huili
authors.initials: H
authors.lastname: Zheng
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Stratton
authors.forename: Kazuto
authors.initials: K
authors.lastname: Morozumi
authors.forename: Jingling
authors.initials: J
authors.lastname: Jin
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Yanagimachi
authors.forename: Wei
authors.initials: W
authors.lastname: Yan
mesh_terms: D000818:Animals; D003593:Cytoplasm / Q000235:genetics / Q000473:pathology* / Q000648:ultrastructure; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000172:deficiency* / Q000235:genetics; D005260:Female; D006133:Growth Substances / Q000235:genetics* / Q000502:physiology; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D013079:Sperm Maturation / Q000235:genetics*; D013087:Spermatids / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D013091:Spermatogenesis / Q000235:genetics; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D013737:Testis / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure
chemical_list: D006133:Growth Substances; D004248:DNA (Cytosine-5-)-Methyltransferases; C519858:Spem1 protein, mouse