The role of prophage for genome diversification within a clonal lineage of Lactobacillus johnsonii: characterization of the defective prophage LJ771.
Two independent isolates of the gut commensal Lactobacillus johnsonii were sequenced. These isolates belonged to the same clonal lineage and differed mainly by a 40.8-kb prophage, LJ771, belonging to the Sfi11 phage lineage. LJ771 shares close DNA sequence identity with Lactobacillus gasseri prophages. LJ771 coexists as an integrated prophage and excised circular phage DNA, but phage DNA packaged into extracellular phage particles was not detected. Between the phage lysin gene and attR a likely mazE ("antitoxin")/pemK ("toxin") gene cassette was detected in LJ771 but not in the L. gasseri prophages. Expressed pemK could be cloned in Escherichia coli only together with the mazE gene. LJ771 was shown to be highly stable and could be cured only by coexpression of mazE from a plasmid. The prophage was integrated into the methionine sulfoxide reductase gene (msrA) and complemented the 5' end of this gene, creating a protein with a slightly altered N-terminal sequence. The two L. johnsonii strains had identical in vitro growth and in vivo gut persistence phenotypes. Also, in an isogenic background, the presence of the prophage resulted in no growth disadvantage.
Nestlé Research Center, Nestec Ltd., P.O. Box 44, CH-1000 Lausanne 26, Switzerland.
Emmanuel
E
Denou
Raymond David
RD
Pridmore
Marco
M
Ventura
Anne-Cécile
AC
Pittet
Marie-Camille
MC
Zwahlen
Bernard
B
Berger
Caroline
C
Barretto
Jean-Michel
JM
Panoff
Harald
H
Brüssow
D000595:Amino Acid Sequence; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics; D003673:Defective Viruses / Q000235:genetics / Q000254:growth & development; D005814:Genes, Viral / Q000235:genetics; D005816:Genetic Complementation Test; D016680:Genome, Bacterial / Q000235:genetics; D005838:Genotype; D007778:Lactobacillus / Q000235:genetics* / Q000821:virology*; D051150:Methionine Sulfoxide Reductases; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics; D010641:Phenotype; D039002:Prophages / Q000235:genetics* / Q000254:growth & development*; D016415:Sequence Alignment
D004279:DNA, Viral; D010088:Oxidoreductases; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase