Cloned cDNA sequences of the hypoxanthine/guanine phosphoribosyltransferase gene from a mouse neuroblastoma cell line found to have amplified genomic sequences.

Abstract
Cloned c[complementary]DNA sequences of the murine hypoxanthine/guanine phosphoribosyltransferase (HPRT; EC 2.4.2.8) gene were isolated by using a mouse neuroblastoma cell line containing increased levels of a variant HPRT protein. These sequences were used as probes to demonstrate that protein over-production in this cell line is a consequence of at least a 20-fold increase in HPRT mRNA levels resulting from approximately 50-fold amplification of HPRT genomic sequences. The largest cDNA insert so far characterized represents about 70% of the HPRT mRNA sequence. This cDNA possesses regions of homology with mRNA and DNA from Chinese hamster, baboon and human, thus facilitating detailed analysis of this locus in these 4 spp.