Asymmetric cell division: a persistent issue?

Abstract

Heterogeneity within a clonal population of cells can increase survival in the face of environmental stress. In a recent issue of Science, Aldridge et al. (2012) demonstrate that cell division in mycobacteria is asymmetric, producing daughter cells that differ in size, growth rate, and susceptibility to antibiotics.

Figure 1

(A) All cell divisions in rod-shaped bacteria are asymmetric, in that one daughter cell inherits the “new” pole (green) from a previous division and the other inherits the “old” pole (red). In some bacteria, this asymmetry is used to create functional specialization of daughter cells. (B) In C. crescentus, different polar appendages form at the new and old poles, leading to dimorphic daughter cells. (C) In Mycobacterium, cells preferentially grow at the old pole (marked with an arrow). Daughter cells that inherit the old pole, called accelerators, continue growing whereas those inheriting the new pole, called alternators, must form a new growth pole before elongating.