Table 1: Ribonucleases: mechanism of action and known virulence targets/phenotypes in Gram-positive pathogens.

Ribonuclease (name of the gene)Mechanism of actionResultncRNA or protein partnerTargets in virulence/phenotype/commentsOrganismRefrence

PNPase (PNP)3′ to 5′ exoribonucleolyticRepressionEssential for cold stress response/affects global mRNA turnoverS. aureus[4]
RNase P (rnpA)EndoribonucleolyticRepressionAffects expression of a large set of virulence factors/rnpA depleted cells exhibited attenuated virulence in a mouse infection modelS. aureus[75]
RNase III (rnc) dsRNA specific endoribonucleolyticRepressionRNAIIIRepresses multiple mRNA targets encoding virulence factors (spa, coa. SA1000, rot), indirectly activates levels of secreted proteins (Efb)/Δrnc strain was attenuated in a mouse infection modelS. aureus[44, 71, 72, 97]
RNase Y (rny)endoribonucleolyticRepressionAffects expression of virulence factors through agr or independently/affects virulence in silkworm and mouse modelsS. aureus[81, 83]
RNase YEndoribonucleolyticRepressionAffects expression of several virulence factors/affects virulence in silkworm and mouse modelsS. pyogenes [81, 82]
RNases J1/J2 (rnjA/rnjB)Endoribonucleolytic, 5′-3′ exoribonucleolyticRepressionAffect bulk mRNA decay and expression of multiple virulence factorsS. pyogenes[7880]
RNase J2Endoribonucleolytic, 5′-3′ exoribonucleolyticActivationebp operon (pilus proteins)/rnjB is essential for biofilm formationE. faecalis[68]
UnknownActivationFasXStabilizes ska mRNA encoding streptokinaseS. pyogenes[70]
UnknownActivationVR-RNAActivates translation of colA mRNA encoding toxin collagenaseC. perfringens[90]
UnknownRepressionLhrA and HfqRepresses the synthesis of ChiA protein (chitinase)L. monocytogenes[100, 101]
Csn1/ RNase IIIEndoribonucleolytic/dsRNA-specific endoribonucleolyticRepressiontracrRNATargets foreign invading DNA such as plasmid and phagesS. pyogenes, Listeria innocua, Streptococcus mutans, Streptococcus thermophilus [102]
Catalytic ribozymeAlternative splicingActivationRiboswitch with bound c-di-GMPActivates the translation of a putative virulence geneC. difficile[109, 110]
PemKEndoribonucleolyticRepressionAffects global RNA decayB. anthracis [124]
MazF, TxeEndoribonucleolyticRepressionLocalizes with vancomycin resistance genes, confers plasmid stabilizationenterococci[125, 126]
MazFEndoribonucleolyticRepressionCleaves several mRNAs (sraP, spa and hla) encoding virulence factors, and possibly other mRNAsS. aureus[128131, 133]
MazF, VapCEndoribonucleolyticRepressionSeveral TA modules are upregulated during hypoxia and infection of macrophagesM. tuberculosis[113, 135, 136]