title: Basigin null mutant male mice are sterile and exhibit impaired interactions between germ cells and Sertoli cells.
abstract: Basigin (BSG) is a multifunctional glycoprotein that plays an important role in male reproduction since male knockout (KO) mice are sterile. The Bsg KO testis lacks elongated spermatids and mature spermatozoa, a phenotype similar to that of alpha-mannosidase IIx (MX) KO mice. MX regulates formation of N-acetylglucosamine (GlcNAc) terminated N-glycans that participate in germ cell-Sertoli cell adhesion. Results showed that Bsg KO spermatocytes displayed normal homologous chromosome synapsis and progression through meiosis. However, only punctate expression of the round spermatid marker SP-10 in the acrosomal granule of germ cells of Bsg KO mice was detected indicating that spermatogenesis in Bsg KO mice was arrested at the early round spermatid stages. We observed a large increase in the number of germ cells undergoing apoptosis in Bsg KO testes. Using lectin blotting, we determined that GlcNAc terminated N-glycans are linked to BSG. GlcNAc terminated N-glycans were significantly reduced in Bsg KO testes. These observations indicate that BSG may act as a germ cell-Sertoli cell attachment molecule. Loss of BSG significantly reduced adhesion between GC-2 and SF7 cells. Moreover, wild type testes showed strong expression of N-cadherin (CDH2) while expression was greatly reduced in the testes of Bsg KO mice. In addition, the integrity of the blood-testis barrier (BTB) was compromised in Bsg KO testes. In conclusion, although some Bsg KO spermatogonia can undergo normal progression to the spermatocyte stage, BSG-mediated germ cell-Sertoli cell interactions appear to be necessary for integrity of the BTB and spermatocyte progression to mature spermatozoa.
authors.affiliation: Department of Animal Sciences, University of Illinois, Urbana, IL, USA.
authors.forename: Jiajia
authors.initials: J
authors.lastname: Bi
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Li
authors.forename: Fengyun
authors.initials: F
authors.lastname: Sun
authors.forename: Anja
authors.initials: A
authors.lastname: Saalbach
authors.forename: Claudia
authors.initials: C
authors.lastname: Klein
authors.forename: David J
authors.initials: DJ
authors.lastname: Miller
authors.forename: Rex
authors.initials: R
authors.lastname: Hess
authors.forename: Romana A
authors.initials: RA
authors.lastname: Nowak
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D051926:Basigin / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D001814:Blood-Testis Barrier; D002448:Cell Adhesion; D002478:Cells, Cultured; D007248:Infertility, Male / Q000209:etiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D013084:Sperm-Ovum Interactions; D013091:Spermatogenesis
chemical_list: C497887:Bsg protein, mouse; D051926:Basigin; D000117:Acetylglucosamine
keywords: BSG; Basigin; Blood-testis barrier; N-glycans; Spermatogenesis; α-Mannosidase II