sentence: A ‘ spoIIIE trapping assay ’ based on σ ‐ dependent reporters in a transfer ‐ inactive spoIIIE mutant has been used extensively to probe the segment of DNA initially trapped in the prespore compartment , as well as the factors required for chromosome orientation and configuration in the early stages of sporulation ( Wu and Errington , 1998 ; Wu and Errington , 2002 ) .