Cyritestin 1 (CYRN1)

Germ cell cyritestin is a membrane-anchored protein belonging to the ADAM family of proteins. Sequencing of eight human cyritestin cDNA clones revealed that they are identical at their 5' and 3' ends but differ from each other in the length of an internal deletion, the human cyritestin mRNA is alternatively spliced. Internal deletions that are present in some cDNA isoforms do not cause a frameshift in the C-terminal coding region. Analysis of the predicted amino acid sequences demonstrated that the human cyritestin is a polymorphic protein that could include membrane-anchored and soluble forms. Southern blot analysis and characterization of human cyritestin genomic fragments revealed that the human genome contains two copies of the cyritestin gene instead of one as in the mouse. The human CYRN1 and CYRN2 genes were assigned to the region p12-21 of chromosome 8 and q12 of chromosome 16, respectively.