The Bacillus subtilis division protein DivlC is a highly abundant membrane-bound protein that localizes to the division site

Abstract

The Bacillus subtilis divlC gene is involved in the initiation of cell division. It encodes a 14.7 kDa protein, with a potential transmembrane region near the N-terminus. In this paper, we show that DivlC is associated with the cell membrane and, in conjunction with previously published sequence data, conclude that it is oriented such that its small N-terminus is within the cytoplasm and its larger C-terminus is external to the cytoplasm. DivlC is shown to be a highly abundant division protein, present at approximately 50 000 molecules per cell. Using immunofluorescence microscopy, DivlC was seen to localize at the division site of rapidly dividing cells between well-segregated nucleoids. Various DivlC immunostaining patterns were observed, and these correlated with different cell lengths, suggesting that the DivlC localization takes on various forms during the cell cycle. The DivlC immunolocalization patterns are very similar to those of another membrane-bound B. subtilis division protein, DivlB.