HOMOLOGY CLONING OF GTP-CYCLOHYDROLASE-I FROM VARIOUS UNRELATED EUKARYOTES BY REVERSE-TRANSCRIPTION POLYMERASE CHAIN-REACTION USING A GENERAL SET OF DEGENERATE PRIMERS

GTP-cyclohydrolase I is the primary enzyme of tetrahydrobiopterin and folic acid biosynthesis, cDNA fragments of GTP-cyclohydrolase I were o btained from rainbow trout, chicken, the fungi Neurospora crassa, Phyc omyces blakesleeanus and Saccharomyces cerevisiae, the cellular slime mold Dictyostelium discoideum, the phytoflagellate Euglena gracilis an d the higher plant Mucuna hassjo using primers specific for conserved regions of the open reading frame and the reverse transcription polyme rase chain reaction (RT-PCR) technique. A number of regions were found to be strictly conserved between unrelated eukaryotes. These regions may be essential for the function of GTP-cyclohydrolase I and are disc ussed with respect to the recently resolved crystal structure of the E scherichia coli enzyme. (C) 1995 Academic Press, Inc.