Abstract: The authors used digital differential display data in NCBI to clone Rcet2 which was isolated from adult mouse testis cDNA library.Sequence analysis revealed that Rcet2 cDNA was 454 bp in length,and had three exons,with the result that these cDNAs encoded one protein.The deduced protein was 88 residues in length and had one potential signal peptide and one cystatin domain,but lacked part critical consensus sites important for cysteine protease inhibition.These characteristics are seen in Cres subgroup,which is related to the family 2 cystatains.RT-PCR analysis showed that Rcet2 was specifically expressed in adult mouse testis,epididymis and cerebrum,but higher in testis than in epididymis and cerebrum.This Rcet2 may be new members of Cres subgroup of family 2 cystatins.

Key words: Rcet2, new gene, reproduction tract, cystatains