MOLECULAR-CLONING, CHROMOSOMAL LOCALIZATION, AND EXPRESSION ANALYSIS OF CYRN1 AND CYRN2, 2 HUMAN GENES-CODING FOR CYRITESTIN, A SPERM PROTEIN INVOLVED IN GAMETE INTERACTION

Germ cell cyritestin is a membrane-anchored protein belonging to the A DAM family of proteins, Sequencing of eight human cyritestin cDNA clon es revealed that they are identical at their 5' and 3' ends but differ from each other in the length of an internal deletion, suggesting tha t the human cyritestin mRNA is alternatively spliced. Internal deletio ns that are present in some cDNA isoforms do not cause a frameshift in the C-terminal coding region, Analysis of the predicted amino acid se quences demonstrated that the human cyritestin is a polymorphic protei n that could include membrane-anchored and soluble forms, Southern blo t analysis and characterization of human cyritestin genomic fragments revealed that the human genome contains two copies of the cyritestin g ene instead of one as in the mouse. The human CYRN1 and CYRN2 genes we re assigned to the region p12-21 of chromosome 8 and q12 of chromosome 16, respectively. Northern blot and RT-PCR analyses revealed that bot h human genes are expressed in the testis, Amino acid sequence compari sons between cyritestin and other members of the metalloprotease-disin tegrin family of proteins suggested that human and mouse cyritestin an d monkey tMDCI are homologous molecules.