ABSTRACT:
Haemophilus influenzae is a genetically transformable bacterium that is different from Escherichia coli in certain aspects of DNA repair. For example, H.influenzae does not exhibit an adaptive response or appear to have an inducible, error-prone repair system. However, H.influenzae does appear to have a nucleotide excision repair system that is very similar to that of E.coli. Evidence for this assertion was provided by Ron Walter and Johan Stuy when they cloned, characterized and sequenced the H.influenzae mutB+ gene. They concluded that this gene coded for a helicase II type enzyme because the base sequence of mutB+ gene was considerably homologous to the E.coli uvrD gene, and when present in a low-copy number plasmid, was able to complement the UV sensitivity of E.coli uvrD mutants.
The H.influenzae uvr-1+ gene has now been cloned. It codes for a protein similar to the E.coli UvrC protein. This conclusion is supported by the following observations. First, the uvr-1+ gene, when present in low-copy number plasmid, complements the UV sensitivity of E.coli uvrC mutants. Second, the base sequence of the uvr-1+ gene shows considerable homology to the uvrC gene.