Biology subjects

Denham, E. L.

Publications and source records attributed to Denham, E. L..

2 recordsLinked to original sources

bioRxiv2026

SpoVG and the Kre-ComK Regulatory Module Orchestrate Production of the EPE Toxin in Bacillus subtilis

Survival of bacteria in their natural habitat requires dynamic responses and adaptation to environmental cues. In Bacillus subtilis, one adaptive strategy is cannibalism, a form of programmed cell death during post-exponential development. Cannibalism enhances multicellular differentiation by prolonging or preventing commitment to endospore formation under starvation conditions. B. subtilis produces three cannibalism toxins: the sporulation delay protein, the sporulation killing factor, and the epipeptide EPE. Production of the latter is encoded in the epeXEPAB operon. Expression of this operon is transcriptionally controlled by the stationary phase regulators Spo0A and AbrB. Here, we demonstrate that EPE production is also post-transcriptionally regulated by two RNA binding proteins, Kre and SpoVG. Deletion of comK, the master regulator of competence development, abolished EPE production. This defect was reversed by additionally deleting kre. The RNA-binding protein, Kre, binds the epeX transcript and acts as a bidirectional ComK repressor, indicating that ComK indirectly regulates EPE biosynthesis via Kre. A second RNA-binding protein, SpoVG, also binds to the epeX mRNA. While Kre acts as a negative regulator, SpoVG was essential for EPE production. These findings reveal a novel regulatory connection between competence and cannibalism, expanding our understanding of how programmed cell death is coordinated in B. subtilis. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/716078v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@1c71c02org.highwire.dtl.DTLVardef@ffdcbborg.highwire.dtl.DTLVardef@1f4a181org.highwire.dtl.DTLVardef@1975dc8_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2019

Novel regulation from novel interactions: Identification of an RNA sponge that controls the levels, processing and efficacy of the RoxS riboregulator of central metabolism in Bacillus subtilis

Small RNAs (sRNAs) are a taxonomically-restricted but transcriptomically-abundant class of post-transcriptional regulators. While potentially of importance, we know the function of few. This is in no small part because we lack global-scale methodology enabling target identification, this being especially acute in species without known RNA meeting point proteins (e.g. Hfq). We apply a combination of psoralen RNA cross-linking and Illumina-sequencing to identify RNA-RNA interacting pairs in vivo in Bacillus subtilis, resolving previously well-described interactants. Although sRNA-sRNA pairings are rare (compared with sRNA/mRNA), we identify a robust example involving the unusually conserved sRNA (RoxS/RsaE) and an unstudied sRNA that we term Regulator of small RNA A (RosA). This interaction is found in independent samples across multiple conditions. Given the possibility of a novel associated regulatory mechanism, and the rarity of well-characterised bacterial sRNA-sRNA interactions, we mechanistically dissect RosA and its interactants. RosA we show to be a sponge RNA, the first to be described in a Gram-positive bacterium. RosA interacts with at least two sRNAs, RoxS and FsrA. Unexpectedly, it acts differently on each. As expected of a sponge RNA, FsrA is sequestered by RosA. The RosA/RoxS interaction is more complex affecting not only the level of RoxS but also its processing and efficacy. Importantly, RosA provides the condition-dependent intermediary between CcpA, the key regulator of carbon metabolism, and RoxS. This not only provides evidence for a novel, and functionally important, regulatory mechanism, but in addition, provides the missing link between transcriptional and post-transcriptional regulation of central metabolism.

microbiology↗