Dependencies for the activation of the cell type-specific sporulation sigma factors.

<p>(A) qRT-PCR analysis of <i>gpr</i>, <i>spoIIIAA</i>, <i>sspA</i> and <i>cotE</i> gene transcription in strain 630Δ<i>erm</i> (wt), and in congenic <i>sigF</i>, <i>sigE</i>, <i>sigG</i> and <i>sigK</i> mutants. RNA was extracted from cells collected 14 hours (<i>gpr</i> and <i>spoIIIAA</i>), 19 hours (<i>sspA</i>) and 24 hours (<i>cotE</i>) after inoculation in SM liquid medium. Expression is represented as the fold ratio between the wild type (wt) and the indicated mutants. Values are the average ± SD of two independent experiments. (B) Cell type-specific expression of transcriptional fusions of the <i>gpr</i>, <i>spoIIIAA</i>, <i>sspA</i> and <i>cotE</i> promoters to <i>SNAP^Cd</i> in the wild type and in the indicated congenic mutants. For each of the strains, expressing the indicated fusions, cells were collected from SM cultures 24 h after inocculation and labeled with TMR-Star (red) and with the membrane dye MTG (green). Following labeling, the cells were observed by phase contrast (PC) and fluorescence microscopy. Merge is the overlap between the TMR-Star (red) and MTG (green) channels. The images are ordered, and the morphological classes defined as in the legend for <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003782#pgen-1003782-g004" target="_blank">Figure 4</a>. The numbers refer to the percentage of cells at the represented stage showing SNAP fluorescence. The data shown are from one experiment, representative of three independent experiments. The number of cells analysed for each class, n, is as follows: class <i>a</i>, 30–50; class <i>b</i>, n = 50–60; class <i>c</i>, n = 30–40; class <i>d</i>, n = 15–25; for <i>sigF/E</i> mutants, n = 80–120; for <i>sigG</i> and <i>sigK</i> mutants, n = 40–50. Scale bar: 1 µm.