title: Transformation in Streptococcus pneumoniae: formation of eclipse complex in a coiA mutant implicates CoiA in genetic recombination.
abstract: CoiA is a transient protein expressed specifically during competence and required for genetic transformation in Streptococcus pneumoniae, but not for DNA uptake. It is widely conserved among Gram-positive bacteria but its function is unknown. Here we report that although the rate of DNA uptake was not affected in a coiA mutant, the internalized donor DNA did not recombine into the host chromosome to form a physical and genetic heteroduplex. Instead, DNA taken up by a coiA mutant accumulated in the form of a single-stranded (ss) DNA-protein complex indistinguishable from the eclipse complex formed as a recombination intermediate in wild-type competent cells. Internalized donor DNA in a dprA mutant did not accumulate either as ss DNA or as an eclipse complex. Together, these results establish that a coiA mutant exhibits a phenotype different from that of dprA or recA mutants, and that CoiA functions at a later step in promoting recombination during genetic transformation in Streptococcus pneumoniae.
authors.affiliation: Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Bhushan V
authors.initials: BV
authors.lastname: Desai
authors.forename: Donald A
authors.initials: DA
authors.lastname: Morrison
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006906:Hydroxyphenylazouracil / Q000494:pharmacology; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009692:Nucleic Acid Heteroduplexes; D011995:Recombination, Genetic; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics*; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; C519997:CoiA protein, Streptococcus pneumoniae; D004277:DNA, Single-Stranded; C093815:DprA protein, bacteria; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009692:Nucleic Acid Heteroduplexes; D006906:Hydroxyphenylazouracil