Mouse and human GTPBP2, newly identified members of the GP-1 family of GTPase

We earlier identified the GTPBP1 gene which encodes a putative GTPase struc turally related to peptidyl elongation factors. This finding was the result of a search for genes, the expression of which is induced by interferon-ga mma in a macrophage cell line, THP-1. In the current study, we probed the e xpressed sequence tag database with the deduced amino acid sequence of GTPB P1 to search for partial cDNA clones homologous to GTPBP1. We used one of t he partial cDNA clones to screen a mouse brain cDNA library and identified a novel gene, mouse GTPBP2, encoding a protein consisting of 582 amino acid s and carrying GTP-binding motifs. The deduced amino acid sequence of mouse GTPBP2 revealed 44.2% similarity to mouse GTPBP1. We also cloned a human h omologue of this gene from a cDNA library of the human T cell line, Jurkat, GTPBP2 protein was found highly conserved between human and mouse (over 99 % identical), thereby suggesting a fundamental role of this molecule across species. On Northern blot analysis of various mouse tissues, GTPBP2 mRNA w as detected in brain, thymus, kidney and skeletal muscle, but was scarce in liver. Level of expression of GTPBP2 mRNA was enhanced by interferon-gamma in THP-1 cells, HeLa cells, and thioglycollate-elicited mouse peritoneal m acrophages. In addition, we determined the chromosomal localization of GTPB P1 and GTPBP2 genes in human and mouse. The GTPBP1 gene was mapped to mouse chromosome 15, region E3, and human chromosome 22q12-13.1, while the GTPBP 2 gene is located in mouse chromosome 17, region C-D, and human chromosome 6p21-12. (C) 2000 Academic Press.