Deletion analysis of gene minE which encodes the topological specificity factor of cell division in Escherichia coli

Abstract

Division inhibition caused by the minCD gene products of Escherichia coli is suppressed specifically at mid-cell by MinE protein expressed at physiological levels. Excess MinE allows division to take place also at the poles, leading to a minicell-forming (Min-) phenotype. In order to investigate the basis of this topological specificity, we have analysed the ability of truncated derivatives of MinE to suppress either minCD-dependent division inhibition in a chromosomal delta(minB) background, or the division inhibition exerted by MinCD at the cell poles in a minB+ strain. Our results indicate that these two effects are not mediated by identical interactions of MinE protein. In addition, gel filtration and the yeast two-hybrid system indicated that MinE interacts with itself by means of its central segment. Taken together, our results favour a model in which wild-type MinE dimer molecules direct the division inhibitor molecules to the cell poles, thus preventing polar divisions and allowing non-polar sites to divide. This model explains how excess MinE, or an excess of certain MinE derivatives which prevent the accumulation of the division inhibitor at the poles, can confer a Min- phenotype in a minB+ strain.

Dynamic assembly of MinD on phospholipid vesicles regulated by ATP and MinE

“…The E. coli K12 strain JS964 (MC1061 malP::lacI q ⌬min::kan) was used in this study (15). The plasmids pZH106 (gfp-minD) and pZH115 (minD) have been described (14).…”

The dimerization and topological specificity functions of MinE reside in a structurally autonomous C‐terminal domain

“…1B, wild-type MinE (MinE 1-88 ) has 12 potential trypsin cleavage sites distributed throughout the protein, including seven within the segment 23-81 that was previously shown to encode the topological specificity function (Zhao et al, 1995;Pichoff et al, 1995). Digestion of MinE 1-88 with trypsin led to the rapid production of a proteolytic fragment of approximately 7 kDa, which remained resistant to further trypsin cleavage (Fig.…”

“…After digestion of MinE 1-88 with trypsin for 15 min, an aliquot of the final reaction mixture was analysed using mass spectrometry, and the 7 kDa fragment was purified from the remaining sample by gel filtration chromatography and subjected to N-terminal sequencing. (Pichoff et al, 1995;Zhao et al, 1995;Zhang et al, 1998), presumably reflecting the ability of these fragments to compete with wild-type MinE for a midcellular target molecule that is critical for its topological specificity function (Zhang et al, 1998 (Kralicek et al, 1993).…”

“…However, these N-terminal fragments counteract MinCD promiscuously at both polar and central division sites (Zhao et al, 1995;Pichoff et al, 1995); thus, they lack topological specificity. The domain responsible for topological specificity appears to reside in the region MinE , based on C-terminal deletion analysis (Zhao et al, 1995) and on the demonstration that the expression of MinE or MinE interferes with the topological specificity function of wildtype MinE (Zhao et al, 1995;Pichoff et al, 1995;Zhang et al, 1998). In this paper, we address the question of whether the topological specificity function of MinE resides in a structurally independent domain.…”

Modeling Three-Dimensional Spatial Regulation of Bacterial Cell Division (Dissertation)

“…by Shih et al (2002). The simulated E-ring, nonetheless, is more dispersed than its in vivo counterpart possibly because we did not consider MinE oligomerization (Pichoff et al, 1995;Zhang et al, 1998) and/or MinD polymerization (Shih et al, 2003), both of which can substantially reduce the diffusion coefficient and sharply increase the subunit density at the localization site. In addition, a significant portion of the E-ring is composed of MinE that is transiently attached to the membrane independent of MinD (shown in cyan in Figure 4.1A and 4.1C).…”