Transcription factor Spo0A switches the localization of the cell division protein FtsZ from a medial to a bipolar pattern in Bacillus subtilis.

Abstract

Entry into sporulation by the Gram-positive bacterium Bacillus subtilis is governed by two transcription factors, SpoOA and cr H, and involves a switch in the site of division from a medial to a polar location. We report that at the onset of sporulation, assembly of the cell division protein FtsZ shifts from midcell to potential division sites near both poles. The switch to a bipolar pattern of FtsZ localization is dependent on Spo0A. Additionally, synthesis of an activated form of Spo0A during growth artificially activates the switch in FtsZ localization and results in the formation of polar septa. The o a factor, on the other hand, is dispensable for the switch in the position of the FtsZ assembly site, although it is required for formation of the polar septum. Our results suggest that during the transition from growth to sporulation, Spo0A induces the expression of genes that suppress FtsZ assembly at the midcell site and activate sites at both poles, whereas O "H induces genes required for a subsequent step in cytokinesis.

Dominant C‐terminal deletions of FtsZ that affect its ability to localize in Caulobacter and its interaction with FtsA

“…Counterstaining to visualize DNA was achieved by adding a final concentration of 10 g ml ¹1 propidium iodide 10 min before the end of the secondary antibody incubation. Under our labelling conditions, propidium iodide only labels DNA because the RNA is degraded by a contaminating RNase in the lysozyme (Levin and Losick, 1996). We confirmed that the intensity of staining by propidium iodide was not affected by treating the cells with RNase (not shown).…”

The division during bacterial sporulation is symmetrically located in Sporosarcina ureae

“…The symmetrical position of the vegetative division septum, as indicated by the FtsZ band, was not surprising. In contrast, the symmetrical location of the septum in sporulating S. ureae was surprising, because it was strikingly different from the asymmetrical location observed for sporulating B. subtilis (Levin and Losick, 1996). Several lines of evidence make us confident that we were indeed observing sporulating cells (as distinct from vegetative cells): (i) the cells were expressing spoIIA-lacZ, which is an early sporulationspecific event; (ii) the cells expressing ␤-galactosidase from the spoIIA-lacZ fusion were only observed in samples taken after the end of exponential growth -as with B. subtilis, the end of exponential growth is defined as the start of sporulation; (iii) no subsequent division was observed during sporulation of S. ureae.…”

“…1A). Since FtsZ protein assembles at the site of septum formation, the band is presumed to indicate a cell division occurring perpendicular to the plane of the image, as has been observed with B. subtilis (Levin and Losick, 1996) and Escherichia coli (Bi and Lutkenhaus, 1991;Addinall et al, 1996). The ring pattern is presumed to indicate a division in the plane of the image.…”

“…Examples are shown in Fig. 1B and C. In B. subtilis, E -directed genes, such as cotE, are expressed after the sporulation septum has been completed (Harry et al, 1995;Zhang et al, 1996), by which time FtsZ is no longer localized at the septum (Levin and Losick, 1996). In S. ureae strain SL6920 containing pLZ72, no FtsZ band or ring was seen in any cells taken from cultures that were expressing cotE-lacZ (data not shown).…”

“…The FtsZ protein is associated with the initiation of cell division in all species of bacteria that have been studied and forms an annular structure at the site of the division septum (Lutkenhaus, 1993;Wang and Lutkenhaus, 1996). FtsZ has been shown to be associated with both the symmetrically located vegetative division septum and the asymmetrically located sporulation division septum in B. subtilis (Levin and Losick, 1996). Our analysis of FtsZ bands in S. ureae indicates that the location of the band during sporulation shows the same symmetry as that observed during vegetative division, in sharp contrast to the situation with B. subtilis (Levin and Losick, 1996).…”