It takes two to tango: YvfTU and DesKR two component systems regulate ABC transporter transcription

DE MENDOZA DIEGO; FERNANDEZ PILAR; MANSILLA MARÍA CECILIA; ALBANESI DANIELA

Paraná

Congreso; LIV Reunión Anual SAIB; 2018

Two component systems (TCS) play a major role in signal transduction in prokaryotes for cellular adaptation to environmental conditions and stresses. In Bacillus subtilis, the DesKR TCS can detect changes in membrane fluidity upon a temperature downshift and induce the expression of a fatty acid desaturase, encoded by the des gene, allowing cell adaptation to cold shock. It has been previously demonstrated that overexpression of DesR in a desK null mutant results not only in the induction of the des gene, but also of the operon yvfRSTU, encoding a putative ABC transporter (YvfRS) and a TCS (YvfTU). Bioinformatic analysis of this operon revealed that YvfTU is highly similar to DesKR and the promoter region upstream of yvfR (PyvfR) to the regulatory region of des. We previously demonstrate that YvfTU can perceive temperature changes, inducing the expression of YvfRS only at 37°C, and that DesKR is also required for this induction.In this work we demonstrated by electrophoretic mobility shift assays that such phenotype was due to a joint regulation of YvfRS ABC transporter by both TCS. Only if DesR and YvfU act together, a slow migrating complex is formed. This result was confirmed by in vivo analysis of mutant strains, which also revealed that unphosphorylatedDesR was involved in the induction of the transporter. Finally, by molecular modeling we analyzed the formation of a heterodimer between both regulators, which was tested in vitro and in vivo.Our findings illustrate one of the few examples in which bacteria use two high homologous TCSs to adjust gene expression and adapt the organisms to a new environmental condition.