Deletion of the novel gene mother cell lysis X results in Cry1Ac encapsulation in the HD73.

The novel protein MclX (mother cell lysis X) in subsp. strain HD73 ( HD73) was characterized in this work. MclX has no known domain and its gene deletion in HD73 resulted in Cry1Ac encapsulation in the mother cell and did not influence Cry1Ac protein production or insecticidal activity. cell wall hydrolysis experiments showed that MclX cannot hydrolyze the cell wall. In deletion mutants, the expression of (which encodes a key cell wall hydrolase) was significantly decreased, as shown by the β-galactosidase activity assay. MclX cannot directly bind to the promoter, based on the electrophoretic mobility shift assay (EMSA). The was reported to be regulated by σ and GerE. However, the transcriptional activities of and showed no difference between HD73 and the deletion mutant. It is indicated that MclX influenced expression independently of σ or GerE, through a new pathway to regulate expression. deletion could be a new approach for insecticidal protein encapsulation in .