Open AccessCharacterization of a suppressor mutation complementing an acid‐sensitive mutation in Streptococcus mutans
Author(s) -
Lis Maciej,
Kuramitsu Howard K.
Publication year - 2003
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/s0378-1097(03)00818-8
Subject(s) - mutant , suppressor mutation , biology , suppressor , genetics , mutation , plasmid , gene , streptococcus mutans , homologous recombination , allele , phenotype , microbiology and biotechnology , bacteria
We isolated a spontaneous suppressor mutant complementing the acid‐sensitive phenotype of Streptococcus mutans strain Tn‐1, a mutant previously generated in this laboratory, defective in the activity of the dgk ‐encoded putative undecaprenol kinase. A relatively simple genetic method was developed to identify the suppressor mutation, based on selection for transformants containing two closely linked markers: a selectable allele of the unknown suppressor gene and an antibiotic resistance gene introduced on a suicide plasmid at random sites into the chromosome via homologous recombination. While we have not actually identified the original suppressor mutation, another mutated gene restoring acid resistance has been isolated, which suggests a possible mechanism of suppression.