Regulation of polyhydroxyalkanoate synthases (phaC1 and phaC2) gene expression in Pseudomonas corrugata
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- Conte, E., Catara, V., Greco, S. et al. Appl Microbiol Biotechnol (2006) 72: 1054. doi:10.1007/s00253-006-0373-y
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In this study we examined polyhydroxyalkanoate (PHA) synthases phaC1 and phaC2 gene expression in two strains of Pseudomonas corrugata (Pc) grown in a minimum mineral medium with related (oleic acid and octanoate) or unrelated (glucose) carbon sources. Analysis of transcription was performed by Northern blot and conventional reverse transcriptase (RT) polymerase chain reaction (PCR). In addition, we developed a RT-real-time PCR method to quantitatively evaluate phaC1Pc and phaC2Pc gene expression. Primers and a TaqMan probe were designed for the specific detection of both synthase transcripts as well as of the housekeeping 16S rRNA, and the relative expression of target genes was calculated. We showed that phaC1Pc and phaC2Pc were not cotranscribed and, on the contrary, were independently regulated. In cultures grown with oleic acid as the sole carbon source, only the expression of phaC1Pc was induced (a tenfold increase after 72 h of culture), whereas that of phaC2Pc remained unchanged. In cultures grown with glucose or sodium octanoate, the expression of both phaC1Pc and phaC2Pc was upregulated but at different rates. Cellular PHA content was compared to the gene expression of the PHA synthases and significant correlations were found between PHA production and phaC1Pc/phaC2Pc expression.