Spatio-temporal regulation of peptidoglycan synthesis by the actin-like protein MreB

Abstract

The actin-like protein MreB regulates cell shape in many bacteria by localizing PG synthesis machinery during lateral growth. In Caulobacter crescentus, MreB plays an additional role by recruiting the stalk biosynthesis complex. In this project, we characterized a mreB point mutant referred to as mreB*, which is stalkless even in conditions known to strongly elongate the stalk such as in low phosphate concentration. We localized the sites of active PG synthesis in mreB* using HADA labelling and the MreB* protein using fluorescent protein fusion and immunofluorescence microscopy. The localization of proteins involved in PG synthesis was also investigated in mreB*. Moreover, we tested the physical interaction between those PG-related proteins and MreB or MreB*, as well as the genetic interactions between loss-of-function alleles of the corresponding genes and mreB*. Finally, a genetic screen was performed in order to find suppressors of the stalkless phenotype displayed by mreB*. Our work allowed to identify several hydrolytic enzymes whose localization and/or activity could be regulated by MreB and to refine the model of the spatio-temporal regulation of PG synthesis/remodelling by MreB in C. crescentus.

Date of Award	20 Jan 2022
Original language	English
Awarding Institution	University of Namur
Supervisor	Regis Hallez (Supervisor)