Abstract
One mechanism for achieving accurate placement of the cell division machinery is via Turing patterns, where non-linear molecular interactions spontaneously produce spatiotemporal concentration gradients. The resulting patterns are dictated by cell shape. For example, the Min system of
Escherichia coli
shows spatiotemporal oscillation between cell poles, leaving a mid-cell zone for division. The universality of pattern-forming mechanisms in divisome placement is currently unclear. We examined the location of the division plane in two pleomorphic archaea,
Haloferax volcanii
and
Haloarcula japonica
, and show that it correlates with the predictions of Turing patterning. Time-lapse analysis of
H. volcanii
shows that divisome locations after successive rounds of division are dynamically determined by daughter cell shape. For
H. volcanii
, we show that the location of DNA does not influence division plane location, ruling out nucleoid occlusion. Triangular cells provide a stringent test for Turing patterning, where there is a bifurcation in division plane orientation. For the two archaea examined, most triangular cells divide as predicted by a Turing mechanism, however, in some cases multiple division planes are observed resulting in cells dividing into three viable progeny. Our results suggest that the division site placement is consistent with a Turing patterning system in these archaea.
In many organisms, there appears to be an intimate link between cell shape and division plane location. By studying division plane placement in live cells of haloarchaea, which show a wide variety of cell shapes, the results show that the division plane dynamically responds to cell shape, consistent with regulation by an underlying Turing patterning system.