Genetic characterization of gram-positive homologs of the XerCD site-specific recombinases.
Homologs of the XerCD enzymes, which in Escherichia coli have been shown to be responsible for resolving chromosomal multimers prior to chromosome segregation, were identified in the genomes of Staphylococcus aureus and Streptococcus pneumoniae. Phylogenetic and conservation pattern analysis suggests that the S. aureus gene products are orthologs of XerC and D. A S. aureus xerC null mutant displayed in vitro characteristics consistent with the segregation defect reported for E. coli xer mutants, and was found to be attenuated in a murine infection model. Strikingly, the S. aureus xerD gene appears to be absolutely required for viability, and may therefore be the first example of an essential gene of the lambda integrase family. In contrast, phylogenetic and conservation pattern analysis show that the S. pneumoniae gene products are more closely related to phage integrases than to XerCD. S. pneumoniae xer1, 2 and 3 null mutants were each found to be attenuated in a murine infection model, suggesting that they may control processes which affect virulence.
SmithKline Beecham Pharmaceuticals, Collegeville, PA 19426-0989, USA. Alison_F_Chalker@sbphrd.com
A F
AF
Chalker
A
A
Lupas
K
K
Ingraham
C Y
CY
So
R D
RD
Lunsford
T
T
Li
A
A
Bryant
D J
DJ
Holmes
A
A
Marra
S C
SC
Pearson
J
J
Ray
M K
MK
Burnham
L M
LM
Palmer
S
S
Biswas
M
M
Zalacain
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002876:Chromosomes, Bacterial / Q000235:genetics; D017124:Conserved Sequence; D004254:DNA Nucleotidyltransferases / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins; D005260:Female; D019426:Integrases; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D011008:Pneumococcal Infections / Q000209:etiology; D045522:Recombinases; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013203:Staphylococcal Infections / Q000209:etiology; D013211:Staphylococcus aureus / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
D029968:Escherichia coli Proteins; D045522:Recombinases; C473360:XerC protein, E coli; D004254:DNA Nucleotidyltransferases; D019426:Integrases; C473361:XerD protein, E coli; C115006:integron integrase IntI1