Mutagenesis of RpoE-like sigma factor genes in <it>Bdellovibrio</it> reveals differential control of <it>groEL</it> and two <it>groES</it> genes

• Main Authors: Lambert Carey, Till Rob, Hobley Laura, Sockett R
• Format: Article
• Language: English
• Published: BMC 2012-06-01
• Series: BMC Microbiology
• Online Access: http://www.biomedcentral.com/1471-2180/12/99

<p>Abstract</p> <p>Background</p> <p><it>Bdellovibrio bacteriovorus</it> HD100 must regulate genes in response to a variety of environmental conditions as it enters, preys upon and leaves other bacteria, or grows axenically without prey. In addition to “housekeeping” sigma factors, its genome encodes several alternate sigma factors, including 2 Group IV-RpoE-like proteins, which may be involved in the complex regulation of its predatory lifestyle.</p> <p>Results</p> <p>We find that one sigma factor gene, <it>bd3314,</it> cannot be deleted from <it>Bdellovibrio</it> in either predatory or prey-independent growth states, and is therefore possibly essential, likely being an alternate sigma 70. Deletion of one of two Group IV-like sigma factor genes, <it>bd0881</it>, affects flagellar gene regulation and results in less efficient predation, although not due to motility changes; deletion of the second, <it>bd0743</it>, showed that it normally represses chaperone gene expression and intriguingly we find an alternative <it>groES</it> gene is expressed at timepoints in the predatory cycle where intensive protein synthesis at <it>Bdellovibrio</it> septation<it>,</it> prior to prey lysis, will be occurring.</p> <p>Conclusions</p> <p>We have taken the first step in understanding how alternate sigma factors regulate different processes in the predatory lifecycle of <it>Bdellovibrio</it> and discovered that alternate chaperones regulated by one of them are expressed at different stages of the lifecycle.</p>