AUTHOR=Zhang Qi , Zhang Ying , Zhang Xiaolei , Zhan Lifang , Zhao Xin , Xu Shungao , Sheng Xiumei , Huang Xinxiang 

TITLE=The novel cis-encoded antisense RNA AsrC positively regulates the expression of rpoE-rseABC operon and thus enhances the motility of Salmonella enterica serovar typhi

JOURNAL=Frontiers in Microbiology

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2015.00990

DOI=10.3389/fmicb.2015.00990

ISSN=1664-302X

ABSTRACT=<p>Bacterial non-coding RNAs are essential in many cellular processes, including response to environmental stress, and virulence. Deep sequencing analysis of the <italic>Salmonella enterica</italic> serovar typhi (<italic>S. typhi</italic>) transcriptome revealed a novel antisense RNA transcribed in <italic>cis</italic> on the strand complementary to <italic>rseC</italic>, an activator gene of sigma factor RpoE. In this study, expression of this antisense RNA was confirmed in <italic>S. typhi</italic> by Northern hybridization. Rapid amplification of cDNA ends and sequence analysis identified an 893 bp sequence from the antisense RNA coding region that covered all of the <italic>rseC</italic> coding region in the reverse direction of transcription. This sequence of RNA was named as AsrC. After overexpression of AsrC with recombinantant plasmid in <italic>S. typhi</italic>, the bacterial motility was increased obviously. To explore the mechanism of AsrC function, regulation of <italic>rseC</italic> and <italic>rpoE</italic> expression by AsrC was investigated. We found that AsrC increased the levels of <italic>rseC</italic> mRNA and protein. The expression of <italic>rpoE</italic> was also increased in <italic>S. typhi</italic> after overexpression of AsrC, which was dependent on <italic>rseC</italic>. Thus, we propose that AsrC increased RseC level and indirectly activating RpoE which can initiate <italic>fliA</italic> expression and promote the motility of <italic>S. typhi</italic>.</p>