Abstract
To successfully propagate, cells need to coordinate chromosomal replication and segregation with cell division to prevent formation of DNA-less cells and cells with damaged DNA. Here, we review molecular systems in Escherichia coli that are known to be involved in positioning the divisome and chromosome relative to each other. Interestingly, this well-studied micro-organism has several partially redundant mechanisms to achieve this task; none of which are essential. Some of these systems determine the localization of the divisome relative to chromosomes such as SlmA-dependent nucleoid occlusion, some localize the chromosome relative to the divisome such as DNA translocation by FtsK, and some are likely to act on both systems such as the Min system and newly described Ter linkage. Moreover, there is evidence that E. coli harbors other divisome-chromosome coordination systems in addition to those known. The review also discusses the minimal requirements of coordination between chromosomes and cell division proteins needed for cell viability. Arguments are presented that cells can propagate without any dedicated coordination between their chromosomes and cell division machinery at the expense of lowered fitness.
Highlights
In most bacteria, the main macromolecular structure that is responsible for coordinating cell division with other cellular processes, including replication and segregation of chromosomes, is the Z-ring (Margolin, 2005; Adams and Errington, 2009; de Boer, 2010; Lutkenhaus et al, 2012)
It was observed that a replication-inhibited and unsegregated nucleoid at mid-cell blocks Z-ring formation independent of the SlmA and SOS response (Cambridge et al, 2014). How these inhibitory effects of nucleoids are mediated at a molecular level is currently not known, but from these data it is clear that the SlmA-related mechanism is not the only one that realizes NO in E. coli cells
Concluding Remarks that the physical size of the nucleoid does not depend on cell size and nucleoids are randomly placed in the cell before division
Summary
The main macromolecular structure that is responsible for coordinating cell division with other cellular processes, including replication and segregation of chromosomes, is the Z-ring (Margolin, 2005; Adams and Errington, 2009; de Boer, 2010; Lutkenhaus et al, 2012). The assembly and disassembly of protofilaments can happen rapidly on the time-scale of seconds (Erickson et al, 2010) This dynamic nature of the Zring makes it susceptible to regulation by numerous protein factors that can tip the balance between the assembly and disassembly of filaments. E. coli cells have developed a number of molecular systems to prevent this outcome. These systems include nucleoid occlusion (NO), the Min system, the Ter linkage, and FtsK translocase (Figure 1). We will review the aforementioned known molecular systems and discuss some hypothetical ones that have been implicated in spatially coordinating the divisome and chromosome. We will limit our discussion to E. coli; coordination systems in other bacterial species show divergent molecular origins (Adams et al, 2014; Monahan et al, 2014). We will expand our scope in the last part of this review where we will discuss the minimal requirements for the coordination between cell division proteins and chromosomes that are necessary for the survival of any cell
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
