Javier Lopez-Garrido: Coordination of cellular processes between different cell-types during Bacillus subtilis sporulation
- Date: Mar 31, 2017
- Time: 11:00 - 12:00
- Speaker: Javier Lopez-Garrido from the University of California, San Diego, USA
- Location: MPI Plön
- Room: Lecture hall
- Host: Paul Rainey
Bacillus subtilis is a bacterium with a simple developmental pathway leading to spore formation under conditions of nutrient limitation. Sporulation starts with an asymmetric cell division (polar septation) giving rise to two cells of unequal size: the smaller forespore and the larger mother cell. Immediately after polar septation, different genetic programs are activated in the forespore and in the mother cell, leading to the production of several sporulation-specific proteins necessary for proper spore development. However, it remains unclear how proteins made before polar septation contribute to sporulation. To address this question, I have developed a system to degrade vegetative proteins in a cell- and developmental stage-specific manner during sporulation to determine their cell-specific requirement after polar septation. The system uses a heterologous ssrA tag from E. coli fused to the C-terminus end of target proteins, and the cognate SspB adaptor protein produced from mother cell- or forespore-specific promoters. This system supports the rapid, ClpXP-mediated degradation of target proteins upon induction of sspB expression. We have constructed a collection of over two hundred ssrA-tagged proteins, which I am using in combination with several microscopy techniques to study different aspects of sporulation. In this talk, I will focus on the mechanism of chromosome translocation between the mother cell and the forespore, and how this process contributes to forespore morphology. My results provide mechanistic insights into how the two cells cooperate to accomplish critical tasks during starvation.