Like ParA, SCO1662 protein, renamed ParJ, is important for accurate chromosome partitioning into prespore compartments (Ditkowski et al., 2010).
The aerial hyphae then undergo synchronous septation and chromosome segregation, subdividing them into prespore compartments that ultimately develop into chains of dormant exospores [ 16].
The other two S. coelicolor SALPs are absent from most species: SsgC, affecting the regularity of sporulation septation and partitioning of DNA into prespore compartments; and SsgF, affecting spore separation (Noens et al., 2005).
The change of cylindrical prespore compartments into ovoid spores involves remodelling and thickening of the cell wall, while inside the developing spore further changes contribute to the onset of dormancy, including chromosome condensation.
The ParA filaments dissociate immediately before sporulation septation and chromosome partitioning take place; and chromosome partitioning into prespore compartments is markedly irregular in the absence of ParA filaments or ParB (Jakimowicz et al., 2007).
(4) The remodelling and thickening of the cell wall of cylindrical, thin-walled prespore compartments, and their separation to generate near-spherical thick-walled spores, are carried out by a multiprotein complex organised by MreB and its paralogue Mbl (Heichlinger et al., 2011; Kleinschnitz et al., 2011).
At the slug stage btg expression is found in scattered cells, mostly in the posterior half of the prespore territory, though sometimes it is also expressed in few cells scattered in the front half of the prespore compartment (Fig. 2D).
Incorporation of DNA into the polar prespore compartment is achieved by anchoring one chromosome copy to the distal pole of the prespore compartment.
During sporulation septation, the uncondensed mass of chromosomes partitions into nucleoids, so that each prespore compartment contains a single copy of the genome.
By Rd7, wild GFP cells are almost entirely absent from prespore compartment, especially in pool 2. In pool 1 (top row), REMI mutant cells are enriched in the collar and back until Rd3.
