The pfam04002 annotation describes RadC as a bacterial DNA repair protein. Although the radC gene is expressed specifically during competence for genetic transformation in Streptococcus pneumoniae, we report that radC mutants exhibit normal uptake and processing of transforming DNA. They also display normal sensitivity to DNA-damaging agents, providing no support for the rad epithet.

Natural genetic transformation is widely distributed in bacteria and generally occurs during a genetically programmed differentiated state called competence. This process promotes genome plasticity and adaptability in Gram-negative and Gram-positive bacteria. Transformation requires the binding and internalization of exogenous DNA, the mechanisms of which are unclear. Here, we report the discov...

The sxy-1 mutation of Haemophilus influenzae causes a 100- to 1,000-fold increase in spontaneous natural competence. We have used mapping and sequencing to identify this mutation as a G-to-A transition in an open reading frame adjacent to the rec-1 locus. This mutation substitutes valine for isoleucine at amino acid 19 of the protein specified by this gene (now named sxy). A multicopy plasmid c...

The mesophile Acinetobacter sp. strain BD413 and the extreme thermophile Thermus thermophilus HB27 display high frequencies of natural transformation. In this study we identified and characterized a novel competence gene in Acinetobacter sp. strain BD413, comA, whose product displays significant similarities to the competence proteins ComA and ComEC in Neisseria and Bacillus species. Transcript...

To identify and map genes involved in competence for genetic transformation in Streptococcus pneumoniae, we have cloned DNA surrounding an ermB insertion mutation that causes a competence factor deficiency. We recovered the insert and approximately 500 base pairs of neighboring pneumococcal DNA in pMB9. Larger pieces of DNA from this region were unstable in pMB9 and pBR325. However, larger piec...

Transformation of resistance to antibiotics was observed in Diplococcus pneumoniae by Hotchkiss (1951, 1952a, 1952b) and in Haemophilus influenzae by Alexander and Leidy (1953) and Alexander et al. (1954). In all these species only certain strains were capable of being transformed. The ability to be transformed has been termed competence; refractory strains are not competent. Austrian (1952) ha...

PREFATORY NOTE........................................................ 228 INTRODUCTION.................................................................................. 229 RESEARCH ON TRANSFORMATION................................................................ 229 Strains....................................................................................... 230 Media...........................

Competence for genetic transformation in Streptococcus pneumoniae is coordinated by the competence-stimulating peptide (CSP), which induces a sudden and transient appearance of competence during exponential growth in vitro. Models of this quorum-sensing mechanism have proposed sequential expression of several regulatory genes followed by induction of target genes encoding DNA-processing-pathway...

Natural competence for transformation is a mode of horizontal gene transfer that is commonly used by bacteria to take up DNA from their environment. As part of this developmental program, so-called competence genes, which encode the components of a DNA-uptake machinery, are expressed. Several models have been proposed for the DNA-uptake complexes of competent bacteria, and most include a type I...

A plasmid library of PstI fragments of Haemophilus influenzae Rd genomic DNA was mutagenized in Escherichia coli with mini-Tn10kan. The mutagenized PstI fragments were introduced by transformation into the H. influenzae chromosome, and kanamycin-resistant transformants were screened for the transformation-deficient phenotype by a cyclic AMP-DNA plate method. Fifty-four mutant strains containing...