Deletion of the cell-division inhibitor MinC results in lysis of Neisseria gonorrhoeae

Abstract

The minCDE genes involved in division site selection in Neisseria gonorrhoeae were identified using raw data from the N. gonorrhoeae genome project and are part of a cluster of 27 genes. When gonococcal min genes were heterologously expressed as a cluster in Escherichia coli, minicells and filaments were produced, indicating that gonococcal min genes disrupted cell division in other genera. The insertional inactivation of the minC gene of N. gonorrhoeae CH811 resulted in a strain (CSRC1) with decreased viability and grossly abnormal cell division as observed by phase-contrast and electron microscopy analysis. Western blot analysis of N. gonorrhoeae CSRC1 confirmed that MinC Ng was not produced. Complementation of CSRC1 by integrating a minC-6WHis tag fusion at the proAB locus by homologous recombination restored viability and 19 times wild-type levels of MinC Ng expression. This slight increase of expression caused a small percentage of the complemented cells to divide aberrantly. This suggested that the 6WHis tag has partially affected the stability of MinC, or that the chromosomal position of minC is critical to its regulation. Comparison of MinC proteins from different bacteria showed a homologous region corresponding to residues 135-230 with five conserved amino acids. Overexpression of MinC Ng in wild-type E. coli cells induced filamentation and an E. coli minC mutant was successfully complemented with minC Ng . Therefore, the evidence indicates that MinC from N. gonorrhoeae acts as a cell-division inhibitor and that its role is essential in maintaining proper division in cocci.

Prokaryotic Development: Emerging Insights

“…The Min proteins are also involved in the determination of cell division site placement in cocci, such as Neisseria gonorrhoeae (98,108). Previously, J. Szeto and other members of the Dillon group (University of Ottawa) showed that MinD selfassociates and that MinD from N. gonorrhoeae (MinD Ng ) is active in E. coli (108).…”

Positioning cytokinesis

“…Although fewer studies have focused on spherical bacteria, it appears that Min or Minlike systems might participate to detect slight alterations in spherical morphology (Huang and Wingreen 2004), thereby determining a long DNA segregation axis, perpendicular to which the Z-ring could be assembled. A canonical Min system has been described in Neisseria and Deinococcus (White et al 1999;Ramirez-Arcos et al 2001). Furthermore, Min-proteins have been shown to undergo oscillations in random orientations in spherical mutant cells of E. coli (Corbin et al 2002).…”

Conserved Glycines in the C Terminus of MinC Proteins Are Implicated in Their Functionality as Cell Division Inhibitors

“…In E. coli, MinC has been shown to block cell division by destabilizing FtsZ rings (10), a protein involved in septal ring formation (20). Overexpression of MinC in E. coli produces a filamentous phenotype indicative of cell division inhibition (5,23). In contrast, inactivation of this protein results in minicell morphology, which is mediated by irregular cell division at the cell poles (5).…”

“…In the diplococcus N. gonorrhoeae, which, unlike E. coli, divides in alternating perpendicular planes (32), inactivation of minC results in enlarged cells with disrupted placement of the septum (23). Interestingly, gonococcal MinC complements an E. coli minC mutant, and its overexpression causes E. coli cells to filament, indicating the common functionality of MinC in the genera Neisseria and Escherichia (23).…”

“…In gram-negative bacteria, such as Neisseria gonorrhoeae and Escherichia coli, this protein acts as a cell division inhibitor in concert with MinD and MinE (5,23). In E. coli, MinC has been shown to block cell division by destabilizing FtsZ rings (10), a protein involved in septal ring formation (20).…”