Cloning of a human tRNA isopentenyl transferase

A cDNA of human origin is shown to encode a tRNA isopentenyl transferase (E .C. 2.5.1.8). Expression of the gene in a Saccharomyces cerevisiae mutant l acking the endogenous tRNA isopentenyl transferase MOD5 resulted in functio nal complementation and reintroduction of isopentenyladenosine into tRNA. T he deduced amino acid sequence contains a number of regions conserved in kn own tRNA isopentenyl transferases. The similarity to the S. cerevisiae MOD5 protein is 53%, and to the Escherichia coli MiaA protein 47%. The human se quence was found to contain a single C2H2 Zn-finger-like motif, which was d etected also in the MOD5 protein, and several putative tRNA transferases lo cated by BLAST searches, but not in prokaryotic homologues. (C) 2000 Elsevi er Science B.V. All rights reserved.