TY - JOUR
T1 - Involvement of extracytoplasmic function sigma factors in virulence regulation in Porphyromonas gingivalis W83
AU - Dou, Yuetan
AU - Osbourne, Devon
AU - McKenzie, Rachelle
AU - Fletcher, Hansel M.
N1 - FEMS Microbiol Lett. 2010 Nov;312(1):24-32. doi: 10.1111/j.1574-6968.2010.02093.x. Epub 2010 Aug 27. Research Support, N.I.H., Extramural
PY - 2010/11
Y1 - 2010/11
N2 - Extracytoplasmic function (ECF) sigma factors are known to play an important role in the bacterial response to various environmental stresses and can significantly modulate their pathogenic potential. In the genome of Porphyromonas gingivalis W83, six putative ECF sigma factors were identified. To further evaluate their role in this organism, a PCR-based linear transformation method was used to inactivate five ECF sigma factor genes (PG0162, PG0214, PG0985, PG1660, and PG1827) by allelic exchange mutagenesis. All five isogenic mutants formed black-pigmented colonies on blood agar. Mutants defective in PG0985, PG1660, and PG1827 genes were more sensitive to 0.25 mM of hydrogen peroxide compared with the wild-type strain. Isogenic mutants of PG0162 and PG1660 showed a 50% decrease in gingipain activity. Reverse transcription-PCR analysis showed that there was no alteration in the expression of rgpA, rgpB, and kgp gingipain genes in these mutants. Hemolytic and hemagglutination activities were decreased by more than 50% in the PG0162 mutant compared with the wild type. Taken together, these findings suggest that ECF sigma factors can modulate important virulence factors in P. gingivalis. ECF sigma factors encoded by the PG0162 and PG1660 genes might also be involved in the post-transcriptional regulation of the gingipains.
AB - Extracytoplasmic function (ECF) sigma factors are known to play an important role in the bacterial response to various environmental stresses and can significantly modulate their pathogenic potential. In the genome of Porphyromonas gingivalis W83, six putative ECF sigma factors were identified. To further evaluate their role in this organism, a PCR-based linear transformation method was used to inactivate five ECF sigma factor genes (PG0162, PG0214, PG0985, PG1660, and PG1827) by allelic exchange mutagenesis. All five isogenic mutants formed black-pigmented colonies on blood agar. Mutants defective in PG0985, PG1660, and PG1827 genes were more sensitive to 0.25 mM of hydrogen peroxide compared with the wild-type strain. Isogenic mutants of PG0162 and PG1660 showed a 50% decrease in gingipain activity. Reverse transcription-PCR analysis showed that there was no alteration in the expression of rgpA, rgpB, and kgp gingipain genes in these mutants. Hemolytic and hemagglutination activities were decreased by more than 50% in the PG0162 mutant compared with the wild type. Taken together, these findings suggest that ECF sigma factors can modulate important virulence factors in P. gingivalis. ECF sigma factors encoded by the PG0162 and PG1660 genes might also be involved in the post-transcriptional regulation of the gingipains.
KW - ECF sigma factor
KW - Porphyromonas gingivalis W83
KW - Virulence
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U2 - 10.1111/j.1574-6968.2010.02093.x
DO - 10.1111/j.1574-6968.2010.02093.x
M3 - Letter
C2 - 20807237
SN - 0378-1097
VL - 312
SP - 24
EP - 32
JO - FEMS Microbiology Letters
JF - FEMS Microbiology Letters
IS - 1
ER -