Reversal by DNA amplifications of an unusual mutation blocking alkane and alcohol utilization in Pseudomonas putida.
We analyzed the reversion of strains carrying alk208, a mutation in the alkBAC (alkane utilization) region of the Pseudomonas CAM-OCT plasmid. Reversion of alk208 was stimulated 25 to 75-fold by small doses of UV-irradiation. All alkane hydroxylase-positive (AlkB+) revertants proved to be aliphatic alcohol dehydrogenase-positive (AlkC+) as well, whereas AlkC+ revertants could be either AlkB+ or AlkB-. Most of the AlkB- AlkC+ partial revertants produced AlkC- segregants at measurable frequencies. UV-irradiation substantially increased the rate of AlkC- segregation. Most segregants reverted to AlkB+ or AlkC+ at frequencies similar to the original alk208 strain. Dot blot hybridization analyses using cloned probes from various regions of CAM-OCT revealed that the partial revertants contained specific amplications of alk DNA. The endpoints of these amplifications mapped in at least two regions. AlkC- segregants had lost the DNA amplifications.
D000438:Alcohols / Q000378:metabolism; D000473:Alkanes / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D005784:Gene Amplification; D005798:Genes, Bacterial; D009154:Mutation; D010641:Phenotype; D011549:Pseudomonas / Q000235:genetics* / Q000378:metabolism
D000438:Alcohols; D000473:Alkanes; D004269:DNA, Bacterial