Isolation and characterization of human SGT and identification of homologues in Saccharomyces cerevisiae and Caenorhabditis elegans.

We have recently isolated a rat cDNA encoding a novel cellular protein able to interact with the major nonstructural protein NS1 of parvovirus H-1 and have termed this protein SGT, for small glutamine-rich tetratricopeptide repeat (TPR)-containing protein. Here we report the isolation of a cDNA from human placenta encoding the human homologue, human SGT. SGT from rat and human contain 314 and 313 amino acids, respectively, and share 91% sequence identity at the protein level. The highest degree of similarity is present within the central region containing three TPR motifs in tandem array. The similarities, however, also extend beyond this region. Human SGTtranscript was found to be ubiquitously present in all human tissues tested. By fluorescence in situ hybridization analysis we have mapped the human gene to chromosome 19p13. The SGT-coding sequences are evolutionarily conserved, since we could identify genes encoding proteins of similar size and structure in the genomes of Saccharomyces cerevisiae and Caenorhabditis elegans.