Cloning and sequence of the human type II IMP dehydrogenase gene.

Human type II inosine 5'-monophosphate dehydrogenase (EC 1.1.1.205) is the rate-limiting enzyme in de novo guanine nucleotide biosynthesis. Regulated inosine 5'-monophosphate dehydrogenase activity is associated with cellular proliferation, transformation, and differentiation. We cloned and sequenced the entire gene for type II inosine 5'-monophosphate dehydrogenase and here provide details regarding the organization of the gene and its transcriptional start sites. The gene spans approximately 5 kb and is disrupted by 12 introns. The transcriptional start sites were determined by S1 nuclease mapping to be somewhat heterogeneous but predominated at 102 and 85 nucleotides from the translational initiation codon.