RnaG is a small regulatory

non-coding RNA A non-coding RNA (ncRNA) is a functional RNA molecule that is not Translation (genetics), translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally imp ...

encoded by the virulence plasmid of ''

Shigella flexneri ''Shigella flexneri'' is a species of Gram-negative bacteria in the genus ''Shigella'' that can cause diarrhea in humans. Several different serogroups of ''Shigella'' are described; ''S. flexneri'' belongs to group ''B''. ''S. flexneri'' infect ...

'', a Gram-negative pathogenic bacterium that causes human

bacillary dysentery Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis. It is associated with species of bacteria from the family Enterobacteriaceae. The term is usually restricted to ''Shigella'' infections. Shigellosis is caused by one ...

. It is a first

regulatory RNA RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by ...

characterised in ''S. flexneri''. The

RNA Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...

is 450

nucleotide Nucleotides are Organic compound, organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both o ...

s long (which makes it one of the largest regulatory sRNAs) and it contains a region with specific secondary structure that interacts with ''icsA'' (
virG
')

mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein. mRNA is ...

and forms a transcription terminator. Acting as

antisense In molecular biology and genetics, the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA, refers to the nature of the roles of the strand and its complement in specifying a sequence of amino acids. Depending on the context, ...

, RnaG is transcribed from the complementary strand of its target, ''icsA'' mRNA. The activity of the incA protein is crucial for spreading of the bacterial pathogen in the host cells.

References

{{DEFAULTSORT:RnaG antisense RNA Antisense RNA