1887

Abstract

Constantly expressed genes are used as internal controls in relative quantification studies. Suitable internal controls for such studies have not yet been defined for . In this study, the genes , , , , and of were compared in terms of expression stability by real-time quantitative RT-PCR. A total of 23 strains with diverse resistance phenotypes were studied. Stability of expression among the housekeeping genes was assessed on the basis of correlation coefficients, with the best-correlated pair accepted as being the most stable one. Eventually, and formed the most stable pair ( = 0.958; < 0.001). Next, in four ciprofloxacin-selected -like mutants, levels of , and mRNA were compared with those of their wild-type counterparts. The comparison was made after correcting the raw values by the geometric mean of the internal control genes and . The level of mRNA was significantly up-regulated, while the gene was down-regulated (although this difference was statistically insignificant), in the mutants. This expression pattern was consistent with that of the expected expression profile of -type mutants; this experiment therefore lends further support to the use of and genes simultaneously as internal controls for such studies.

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2003-05-01
2019-11-12
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