RESUMEN
This paper presents data on the cellular localization of the testis-expressed mouse Cyrn gene product, cyritestin. This cysteine-rich protein is a member of a family including various rodent and primate proteins and snake venom proteins of the metalloproteinase and disintegrin types. By using antibodies raised against recombinant proteins generated in bacteria and against synthetic peptides we show that (i) Cyrn mRNA is present in germ cells 4 days prior to translation; (ii) cyritestin protein is localized in the acrosomal region of spermatids and spermatozoa; and (iii) cyritestin has an apparent molecular weight of 110,000 Daltons, but is subject to processing during epididymal sperm transport, resulting in a shorter molecule lacking approximately 55 kDa from the N-terminal half. We conclude that cyritestin becomes exposed on the sperm surface after successful acrosome reaction and thus may play a role in sperm function rather than in testicular germ cell maturation.
Asunto(s)
Acrosoma/química , Glicoproteínas de Membrana/genética , Metaloendopeptidasas/genética , Biosíntesis de Proteínas/fisiología , Procesamiento Proteico-Postraduccional/fisiología , Proteínas ADAM , Animales , Especificidad de Anticuerpos , Secuencia de Bases , Epidídimo/fisiología , Expresión Génica/fisiología , Inmunohistoquímica , Masculino , Glicoproteínas de Membrana/inmunología , Glicoproteínas de Membrana/aislamiento & purificación , Proteínas de la Membrana/genética , Metaloendopeptidasas/inmunología , Metaloendopeptidasas/aislamiento & purificación , Ratones , Datos de Secuencia Molecular , Péptidos/inmunología , Péptidos/aislamiento & purificación , Transporte Espermático , Factores de TiempoRESUMEN
The chromosomal positions of three genes that are selectively expressed in mouse testis cells have been identified. These genes include (i) TAZ83, which codes for an early- to mid-pachytene germ cell stage-expressed, cysteine-rich transmembrane protein (cyritestin) with homologies to various snake toxins and guinea pig sperm-egg fusion proteins; (ii) TNZ1, which is expressed in neonatal Leydig cells; and (iii) TAZ4, a testis-specific gene isolated by immunoscreening with antiserum raised against Sertoli cell membranes. Our experimental data, derived from chromosomal in situ hybridizations and RFLP studies of genetic backcrosses, indicate that (i) the TAZ83 (cyritestin) gene maps to chromosome 8, band A2, near the Plat locus; (ii) TNZ1 is located in the proximal region of chromosome 11; and (iii) TAZ4 is located at band D in the distal portion of chromosome 11, near the Hlr1 locus, with a related sequence, TAZ4-rs1, in the proximal part of chromosome 1.