Abstract:
Antisense RNAs that originate from the complementary strand of protein coding genes are involved in the regulation of
gene expression in all domains of life. In bacteria, some of these antisense RNAs are transcriptional noise whiles others play
a vital role to adapt the cell to changing environmental conditions. By deep sequencing analysis of transcriptome of
Salmonella enterica serovar Typhi, a partial RNA sequence encoded in-cis to the dnaA gene was revealed. Northern blot and
RACE analysis confirmed the transcription of this antisense RNA which was expressed mostly in the stationary phase of the
bacterial growth and also under iron limitation and osmotic stress. Pulse expression analysis showed that overexpression of
the antisense RNA resulted in a significant increase in the mRNA levels of dnaA, which will ultimately enhance their
translation. Our findings have revealed that antisense RNA of dnaA is indeed transcribed not merely as a by-product of the
cell’s transcription machinery but plays a vital role as far as stability of dnaA mRNA is concerned.
