Y. Wei et al., Global impact of sdiA amplification revealed by comprehensive gene expression profiling of Escherichia coli, J BACT, 183(7), 2001, pp. 2265-2272
In Escherichia coli the amplification of sdiA, a positive activator of ftsQ
AZ, genes that are essential for septation, results in mitomycin C resistan
ce. To help us understand this resistance phenotype, genes whose expression
was altered by increased sdiA dosage were identified using a DNA microarra
y-based, comprehensive transcript profiling method. The expression of 62 ge
nes was reduced by more than threefold; of these, 41 are involved in motili
ty and chemotaxis, Moreover, the expression of 75 genes, 36 of which had be
en previously characterized, was elevated at least threefold, As expected,
increased sdiA dosage led to significantly elevated sdiA and 'ddlB-ftsQAZ-l
pxC operon expression. Transcription of two genes, uvrY and uvrC, located d
ownstream of sdiA and oriented in the same direction, was elevated about 10
-fold, although the intervening gene, yecF, of apposite polarity was unaffe
cted by increased sdiA dosage, Three genes (mioC and gidAB) flanking the re
plication origin, oriC, were transcribed more often when sdiA dosage was hi
gh, as were 12 genes within 1 min of a terminus of replication, terB, Trans
cription of the acrABDEF genes, mapping in three widely spaced loci, was el
evated significantly, while several genes involved in DNA repair and replic
ation (e.g., nei, recN, mioC, and mcrC) were moderately elevated in express
ion. Such global analysis provides a link between septation and the respons
e to DNA-damaging agents.