Chromosomal assignment of three novel mouse genes expressed in testicular cells.

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.