Isolation and characterization of a human cDNA homologous to the Xenopus laevis XCAP-C gene belonging to the structural maintenance of chromosomes (SMC) family

We have isolated a human cDNA encoding a protein of 1288 amino acids that s hows 77% identity in amino acid sequence to XCAP-C, Xenopus chromosome-asso ciated polypeptide-C, belonging to the family of structural maintenance of chromosomes (SMC), which is known to play a crucial role in the proper cond ensation and segregation of mitotic chromosomes. In particular, an almost 2 00-amino-acid domain in the N-terminal, including an NTP-binding motif and that in the C-terminal domain, including a DA-box, were well conserved and showed 95% identity between human and frog, indicating that these two domai ns are functionally very important. The transcript of this gene was express ed ubiquitously in various human tissues, but thymus, testis, and colon see med to express this gene more abundantly. We also determined its chromosoma l location at 3q26.1 by fluorescence in situ hybridization.