Insights into the LexA regulon of Thermotogales.
The lexA genes of Thermotoga maritima and Petrotoga miotherma, both members of the Order Thermotogales, have been cloned and their transcriptional organization, as well as the functional characteristics of their encoded products, analyzed. In both bacterial species, the lexA gene was found to be co-transcribed together with another four (T. maritima) or three (P. miotherma) upstream open-reading frames. The P. miotherma LexA was able to bind promoters of both the cognate lexA encoding operon and the uvrA gene but not to that of the recA. Conversely, LexA protein and crude cell extracts from T. maritima were unable to bind promoters governing the expression of either its lexA or recA genes. In agreement with these observations, no functional copy of the P. miotherma LexA box, corresponding to the GANTN(6)GANNAC motif, seems to be present in the T. maritima genome. Giving support to the proposal that the evolutionary branching order of the Order Thermotogales is very close to that of Gram-positive bacteria, the P. miotherma LexA protein was still able to recognize the previously described LexA-binding sequence for Gram-positive bacteria.
Mazón
Gerard
G
Centre de Recerca en Sanitat Animal, 08193 Bellaterra, Spain.
Campoy
Susana
S
Fernández de Henestrosa
Antonio R
AR
Barbé
Jordi
J
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D023061:Gene Order; D006090:Gram-Negative Bacteria / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D018085:Regulon / Q000235:genetics*; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020124:Thermotoga maritima / Q000235:genetics* / Q000502:physiology; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein