A novel cis antisense RNA AsfD promotes Salmonella enterica serovar Typhi motility and biofilm formation

Regulatory Interplay between RNase III and Antisense RNAs in E. coli: the Case of AsflhD and FlhD, Component of the Master Regulator of Motility

“…Thus, the conservation of the promoter of AsflhD could be the result of direct selection for FlhD activity or for the regulatory function of AsflhD (potentially) controlling the expression of FlhD in these bacteria. In S. enterica serovar Typhi, AsfD, a long asRNA complementary to flhDC and motA mRNAs, was observed as a 2,000-nt fragment by northern blotting in a wt strain ( 56 ). AsfD was implicated in the positive regulation of flhDC during stationary phase by an uncharacterized mechanism.…”

Regulation of biofilm formation by non-coding RNA in prokaryotes

“… Gram-negative bacteria Non-coding RNA Role/Function References Escherichia coli RydC Reduces curli production and biofilm production Bordeau and Felden (2014) Escherichia coli McaS flagellar transcriptional activator Jorgensen et al. (2013) Escherichia coli CsrB and CsrC Sequesters activity of CsrA by binding to it Salmonella typhi AsfD Upregulates flhDC operon Chen et al. (2020) Salmonella typhimurium MicA regulates biofilm formation independent of luxS Kint et al.…”

“…Using molecular genetics, AsfD, a cis antisense RNA, has been identified from S. typhi . AsfD has been shown to interact with flHDC operon, and stimulates the expression of flhDC , upregulates motility and enhances biofilm formation ( Chen et al., 2020 ). In the case of Salmonella typhimurium , Hfq also acts as a master regulator of biofilm formation.…”

The Complex Mechanism of the Salmonella typhi Biofilm Formation That Facilitates Pathogenicity: A Review

“…Non-coding RNAs are a type of regulatory RNA that is not translated into proteins but plays a transcriptional and post-transcriptional regulatory role in gene expression. Authors, such as Chen et al, have discovered a novel cis-encoded lncRNA AsfD encoded by the antisense strand of the flhDC operon [ 54 ]. They observed that AsfD is associated with S. typhi biofilm development and the transcription of AsfD is induced by the regulators OmpR and Fis.…”

“…They observed that AsfD is associated with S. typhi biofilm development and the transcription of AsfD is induced by the regulators OmpR and Fis. AsfD positively regulate S. typhi motility as well as biofilm formation by up-regulating different flagellar genes and the target gene of flhDC operon [ 54 ]. Another novel non-coding RNA (ncRNA), RibS, was found to be associated with biofilm formation in S. typhi .…”