Cis-encoded non-coding antisense RNAs in streptococci and other low GC Gram (+) bacterial pathogens.

Kyu Hong Cho,Jeong-Ho Kim

doi:10.3389/fgene.2015.00110

Kyu Hong Cho, Jeong-Ho Kim

Open Access

https://doi.org/10.3389/fgene.2015.00110

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Abstract

Due to recent advances of bioinformatics and high throughput sequencing technology, discovery of regulatory non-coding RNAs in bacteria has been increased to a great extent. Based on this bandwagon, many studies searching for trans-acting small non-coding RNAs in streptococci have been performed intensively, especially in the important human pathogen, group A and B streptococci. However, studies for cis-encoded non-coding antisense RNAs in streptococci have been scarce. A recent study shows antisense RNAs are involved in virulence gene regulation in group B streptococcus, S. agalactiae. This suggests antisense RNAs could have important roles in the pathogenesis of streptococcal pathogens. In this review, we describe recent discoveries of chromosomal cis-encoded antisense RNAs in streptococcal pathogens and other low GC Gram (+) bacteria to provide a guide for future studies.

Highlights

Non-coding regulatory RNAs exist in all three kingdoms and confer another layer of regulation mechanism for gene expression
Trans-acting small noncoding RNAs are usually encoded in intergenic regions on the chromosome and control translation or degradation of their target mRNAs
Most cis-encoded antisense RNAs are complementary to a small portion of an open reading frame (ORF) and often the complementary portion includes the ribosome-binding site (Figure 1A)

Summary

Introduction

Non-coding regulatory RNAs exist in all three kingdoms and confer another layer of regulation mechanism for gene expression. Most cis-encoded antisense RNAs are complementary to a small portion of an open reading frame (ORF) and often the complementary portion includes the ribosome-binding site (Figure 1A) These small antisense RNAs are widely expressed on the chromosomes, plasmids, and transposons. The three RNAs, which have the sizes of 123 bps, 239 bps, and 243 bps, are fully or partially antisense to coding sequences (CDSs) involved in the pathogenicity of S. agalactiae When they overexpressed two of these antisense RNAs using a multi-copy plasmid, one reduced the expression of the adjacent target gene but the other increased the expression of its target gene.

Streptococcus agalactiae

Name of antisense RNA

Discovered method*

Findings

Northern blot Northern blot