CROSS-REGULATION BETWEEN Bacillus subtilis TWO COMPONENT SYSTEMS DESK-DESR AND YVFT-YVFU

FERNÁNDEZ, P; PORRINI, L; ALBANESI, D; DE MENDOZA, D; MANSILLA, MC

Mar del Plata

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

SAIB

Two componentsystems (TCS) play a major role in adaptation to environmental changes inprokaryotes. In Bacillus subtilis, the DesKR TCScan detect changes in membrane fluidity upon a temperature downshift and inducethe expression of a fatty acid desaturase, encoded by the des gene, allowingcell adaptation to cold shock. B.subtilis possess a DesKR homolog TCS, YvfTU, which regulatesthe expression of yvfRS genes, also in a temperature-dependent fashion. Thesegenes encode a putative ABC transporter, but the transported solutes areunknown. In this work, we investigated whether the similarity of these TCSallows cross-talk between both pathways. First, we built a desR null mutant carrying a transcriptional fusion of PyvfR to lacZwich allow us to evidence that DesR is essential for yvfRS expression. To knowwhich is the phosphorylation state of DesR required for yvfRS expression, wemade complementation tests with a DesR mutant in its phosphorylatable Asp54residue. Also, by in vivo and in vitro assays we prove that DesK is able tophosphorylate YvfU, showing that DesK has an active role in yvfRS activation.On the other hand, YvfTU TCS is not essential for des activation and YvfTcannot interact with DesR. These results suggest that together DesKR and YvfTUTCS regulate the transcription of yvfRS, evidencing one of the few examples of crossregulation known to date.