During sporulation in Bacillus subtilis, expression of developmental genes spoIVCB and cotD is induced in the mother cell compartment of the sporangium at morphological stages IV and V, respectively. A 27-kilodalton RNA polymerase sigma factor called σK (or σ27) has been found that causes weak transcription of spoIVCB and strong transcription of cotD. A 14-kD protein was also discovered that changes the specificity of σK-containing RNA polymerase, greatly stimulating spoIVCB transcription and markedly repressing cotD transcription. Both σK and the 14-kD protein are products of genes known to be required for expression of specific genes in the mother cell. Thus, σK directs gene expression in the mother cell and it is proposed that inactivation or sequestering of the 14-kD protein switches the temporal pattern of gene expression during the transition from stages IV to V of development.
|Number of pages||4|
|State||Published - 1989|