Summary
We have studied the relationship between 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.
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Abbreviations
- FGAR:
-
formyl glycinamide ribotide
- HPRT:
-
hypoxanthine phosphoribosyl transferase
- GPRT:
-
guanine phosphoribosyl transferase
- APRT:
-
adenine phosphoribosyl transferase
- PRPP:
-
5 phosphoribosyl-1 pyrophosphate
- 6MP:
-
6-mercaptopurine
- FA:
-
2-fluoroadenine
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Communicated by E. Bautz
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Levine, R.A., Taylor, M.W. Selection for purine regulatory mutants in an E. coli hypoxanthine phosphoribosyl transferase-guanine phosphoribosyl transferase double mutant. Molec. Gen. Genet. 181, 313–318 (1981). https://doi.org/10.1007/BF00425604
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DOI: https://doi.org/10.1007/BF00425604