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. 1976 Dec;73(12):4589–4593. doi: 10.1073/pnas.73.12.4589

Analysis of HeLa cell hypoxanthine phosphoribosyltransferase mutants and revertants by two-dimensional polyacrylamide gel electrophoresis: evidence for silent gene activation.

G Milman, E Lee, G S Ghangas, J R McLaughlin, M George Jr
PMCID: PMC431556  PMID: 63948

Abstract

The spot corresponding to hypoxanthine phosphoribosyltransferase (HPRT; IMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.8) has been identified in two-dimensional polyacrylamide gels of HeLa cell extracts. This spot is absent in gels of 24 HPRT dificient mutants. A missense mutant displays a new HPRT spot at the same molecular weight but different isoelectric focusing position. Five independently isolated revertants of the missense mutant display spots corresponding to both the wild-type and mutant proteins indicating that they synthesize HPRT from two separate genes. If the missense protein is synthesized from a mutated form of the initially active HPRT gene, then wild-type HPRT protein in the revertants must be snythesized from a newly activated but prevously silent wild-type gene. The newly activated gene in the revertants of the missense mutation appears unstable producing a high frequency of spontaneous HPRT mutants.

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These references are in PubMed. This may not be the complete list of references from this article.

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