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Mol Gen Genet. 1981;181(3):313-8.

Selection for purine regulatory mutants in an E. coli hypoxanthine phosphoribosyl transferase-guanine phosphoribosyl transferase double mutant.

Abstract

We have studied the relationship betwen purine salvage enzymes, 6-mercaptopurine resistance, and the purR phenotype in E. coli. Mutants resistant to 6-mercaptopurine were found to have defects in HPRT, the purR repressor, or in both. Analysis of these mutants led to the isolation of a hypoxanthine phosphoribosyl transferase-guanine phosphoribosyl transferase double mutant (hpt- gpt-) that is extremely sensitive to adenine. Two classes of adenine resistant mutants were isolated from this strain. The first class was deficient in APRT (apt-) while the second class represented purine regulatory mutants (purR-). There is thus selection for the purR phenotype in a hpt- gpt- background.

PMID:
6787390
DOI:
10.1007/bf00425604
[Indexed for MEDLINE]

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