title: Size sensors in bacteria, cell cycle control, and size control.
abstract: Bacteria proliferate by repetitive cycles of cellular growth and division. The progression into the cell cycle is admitted to be under the control of cell size. However, the molecular basis of this regulation is still unclear. Here I will discuss which mechanisms could allow coupling growth and division by sensing size and transmitting this information to the division machinery. Size sensors could act at different stages of the cell cycle. During septum formation, mechanisms controlling the formation of the Z ring, such as MinCD inhibition or Nucleoid Occlusion (NO) could participate in the size-dependence of the division process. In addition or alternatively, the coupling of growth and division may occur indirectly through the control of DNA replication initiation. The relative importance of these different size-sensing mechanisms could depend on the environmental and genetic context. The recent demonstration of an incremental strategy of size control in bacteria, suggests that DnaA-dependent control of replication initiation could be the major size control mechanism limiting cell size variation.
authors.affiliation: UMR1319 Micalis, Institut National de la Recherche Agronomique Jouy-en-Josas, France ; UMR Micalis, AgroParisTech Jouy-en-Josas, France ; Laboratoire Jean Perrin (Université Pierre et Marie Curie-Centre National de la Recherche Scientifique UMR8237), Université Pierre et Marie Curie Paris, France.
authors.forename: Lydia
authors.initials: L
authors.lastname: Robert
keywords: DnaA; FtsZ; MinCD; bacterial cell cycle; incremental model; replication initiation; size control