Spatiotemporally regulated proteolysis to dissect the role of vegetative proteins during Bacillus subtilis sporulation: cell‐specific requirement of σH and σA

• Published in: Molecular microbiology 2018-04, Vol.108 (1), p.45-62
• Main Authors: Riley, Eammon P., Trinquier, Aude, Reilly, Madeline L., Durchon, Marine, Perera, Varahenage R., Pogliano, Kit, Lopez‐Garrido, Javier
• Format: Article
• Language: English
• Subjects: Bacillus subtilis; Biodegradation; Genetic programs; Germination; Proteins; Proteolysis; Spore germination; Sporulation
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.13916

Summary Sporulation in Bacillus subtilis is a paradigm of bacterial development, which involves the interaction between a larger mother cell and a smaller forespore. The mother cell and the forespore activate different genetic programs, leading to the production of sporulation‐specific proteins. A critical gap in our understanding of sporulation is how vegetative proteins, made before sporulation initiation, contribute to spore formation. Here we present a system, spatiotemporally regulated proteolysis (STRP), which enables the rapid, developmentally regulated degradation of target proteins, thereby providing a suitable method to dissect the cell‐ and developmental stage‐specific role of vegetative proteins. STRP has been used to dissect the role of two major vegetative sigma factors, σH and σA, during sporulation. The results suggest that σH is only required in predivisional cells, where it is essential for sporulation initiation, but that it is dispensable during subsequent steps of spore formation. However, evidence has been provided that σA plays different roles in the mother cell, where it replenishes housekeeping functions, and in the forespore, where it plays an unexpected role in promoting spore germination and outgrowth. Altogether, the results demonstrate that STRP has the potential to provide a comprehensive molecular dissection of every stage of sporulation, germination and outgrowth. Spore formation in Bacillus subtilis represents a simple developmental process that involves the interaction between only two cells. Here we present a method, called spatiotemporally regulated proteolysis (STRP), to rapidly deplete target proteins in a cell‐ and developmental stage‐specific manner during sporulation. We show that STRP has the potential to provide a comprehensive molecular dissection of every stage of sporulation, germination and outgrowth.