Small transcriptome analysis indicates that the enzyme RppH influences both the quality and quantity of sRNAs in Neisseria gonorrhoeae

Prokaryotic mRNA turnover can be initiated by the removal of pyrophosphate from the 5' end of a transcript using the RNA pyrophosphohydrolase enzyme RppH. Following the initial dephosphorylation step, RNaseE then degrades the message into small oligonucleotide segments. This study assessed the small RNA transcriptome of Neisseria gonorrhoeae strain MS11 in two genetic backgrounds; using wild type cells as well as cells carrying a rppH insertional mutation. It was found that the presence of the RppH enzyme affected both the quantity and length of small RNAs (sRNAs) in various chromosomal locations and involved sense transcripts (seRNAs), transcripts originating from the opposite strand (asRNAs) as well as inter-genic-derived RNAs (IGRs). In comparing the two transcriptomes, we found that not all small RNAs were expressed in both genetic backgrounds, suggesting that RppH apparently targets only a subset of transcripts. Overall, this study shows that small RNAs can be detected from the majority of genes within the chromosome, as well as from inter-genic regions, and that more sRNA transcripts are detected in the absence of the RppH enzyme.