The Human Cysteine‐Rich Secretory Protein (CRISP) Family

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Abstract
We report the isolation and characterisation of cDNAs encoding three different, human members of the cysteine-rich secretory protein (CRISP) family. The novel CRISP-I exists in five cDNA subtypes differing by the presence or absence of a stretch coding for a C-terminal cysteine-rich domain so far found in all members of the family, and by the length of their 3-untranslated region. CRISP-2 cDNA corresponds to the previously described TPXI form, with so far unreported 5′-untranslated sequence heterogeneities while CRISP-3 cDNA codes for a new, unique protein. Northern blot analysis of various human organs indicates that CRISP-1 transcripts are epididymis-specific whereas CRISP-2/TPXI transcripts are detected mainly in the testis and also in the epididymis. CRISP-3 transcripts are more widely distributed and found predominantly in the salivary gland, pancreas and prostate, and in less abundance in the epididymis, ovary, thymus and colon. A protein reacting with an anti-mouse CRISP-1 antibody was isolated from human epididymal extracts and N-terminal sequencing revealed that it corresponded to the CRISP-1 cDNA we have isolated. In contrast to findings on its rat counterpart epididymal protein DE/acidic epididymal glycoprotein (AEG), no significant association of CRISP-1 with human spermatozoa was observed.