Dataset Information

Transcription of the lysine-2,3-aminomutase gene in the kam locus of Bacillus thuringiensis subsp. kurstaki HD73 is controlled by both ?54 and ?K factors.

ABSTRACT: Lysine 2,3-aminomutase (KAM; EC 5.4.3.2) catalyzes the interconversion of l-lysine and l-?-lysine. The transcription and regulation of the kam locus, including lysine-2,3-aminomutase-encoding genes, in Bacillus thuringiensis were analyzed in this study. Reverse transcription-PCR (RT-PCR) analysis revealed that this locus forms two operons: yodT (yodT-yodS-yodR-yodQ-yodP-kamR) and kamA (kamA-yokU-yozE). The transcriptional start sites (TSSs) of the kamA gene were determined using 5' rapid amplification of cDNA ends (RACE). A typical -12/-24 ?(54) binding site was identified in the promoter PkamA, which is located upstream of the kamA gene TSS. A ?-galactosidase assay showed that PkamA, which directs the transcription of the kamA operon, is controlled by the ?(54) factor and is activated through the ?(54)-dependent transcriptional regulator KamR. The kamA operon is also controlled by ?(K) and regulated by the GerE protein in the late stage of sporulation. kamR and kamA mutants were prepared by homologous recombination to examine the role of the kam locus. The results showed that the sporulation rate in B. thuringiensis HD(?kamR) was slightly decreased compared to that in HD73, whereas that in HD(?kamA) was similar to that in HD73. This means that other genes regulated by KamR are important for sporulation.

SUBMITTER: Zhang Z

PROVIDER: S-EPMC4135644 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature

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Transcription of the lysine-2,3-aminomutase gene in the kam locus of Bacillus thuringiensis subsp. kurstaki HD73 is controlled by both σ54 and σK factors.

Zhang Zhe Z Yang Min M Peng Qi Q Wang Guannan G Zheng Qingyun Q Zhang Jie J Song Fuping F

Journal of bacteriology 20140609 16

Lysine 2,3-aminomutase (KAM; EC 5.4.3.2) catalyzes the interconversion of l-lysine and l-β-lysine. The transcription and regulation of the kam locus, including lysine-2,3-aminomutase-encoding genes, in Bacillus thuringiensis were analyzed in this study. Reverse transcription-PCR (RT-PCR) analysis revealed that this locus forms two operons: yodT (yodT-yodS-yodR-yodQ-yodP-kamR) and kamA (kamA-yokU-yozE). The transcriptional start sites (TSSs) of the kamA gene were determined using 5' rapid amplifi ...[more]

PMID: 24914178

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Project description:Bacillus thuringiensis is a Gram-positive spore-forming bacterium pathogenic to various insect species. This property is due to the Cry toxins encoded by plasmid genes and mostly produced during sporulation. B. thuringiensis contains a remarkable number of extrachromosomal DNA molecules and a great number of plasmid rap-phr genes. Rap-Phr quorum-sensing systems regulate different bacterial processes, notably the commitment to sporulation in Bacillus species. Rap proteins are quorum sensors acting as phosphatases on Spo0F, an intermediate of the sporulation phosphorelay, and are inhibited by Phr peptides that function as signaling molecules. In this study, we characterize the Rap63-Phr63 system encoded by the pAW63 plasmid from the B. thuringiensis serovar kurstaki HD73 strain. Rap63 has moderate activity on sporulation and is inhibited by the Phr63 peptide. The rap63-phr63 genes are cotranscribed, and the phr63 gene is also transcribed from a σH-specific promoter. We show that Rap63-Phr63 regulates sporulation together with the Rap8-Phr8 system harbored by plasmid pHT8_1 of the HD73 strain. Interestingly, the deletion of both phr63 and phr8 genes in the same strain has a greater negative effect on sporulation than the sum of the loss of each phr gene. Despite the similarities in the Phr8 and Phr63 sequences, there is no cross talk between the two systems. Our results suggest a synergism of these two Rap-Phr systems in the regulation of the sporulation of B. thuringiensis at the end of the infectious cycle in insects, thus pointing out the roles of the plasmids in the fitness of the bacterium.IMPORTANCE The life cycle of Bacillus thuringiensis in insect larvae is regulated by quorum-sensing systems of the RNPP family. After the toxemia caused by Cry insecticidal toxins, the sequential activation of these systems allows the bacterium to trigger first a state of virulence (regulated by PlcR-PapR) and then a necrotrophic lifestyle (regulated by NprR-NprX); ultimately, sporulation is controlled by the Rap-Phr systems. Our study describes a new rap-phr operon carried by a B. thuringiensis plasmid and shows that the Rap protein has a moderate effect on sporulation. However, this system, in combination with another plasmidic rap-phr operon, provides effective control of sporulation when the bacteria develop in the cadavers of infected insect larvae. Overall, this study highlights the important adaptive role of the plasmid Rap-Phr systems in the developmental fate of B. thuringiensis and its survival within its ecological niche.

Dataset Information

Transcription of the lysine-2,3-aminomutase gene in the kam locus of Bacillus thuringiensis subsp. kurstaki HD73 is controlled by both ?54 and ?K factors.

Publications

Transcription of the lysine-2,3-aminomutase gene in the kam locus of Bacillus thuringiensis subsp. kurstaki HD73 is controlled by both σ54 and σK factors.

Similar Datasets

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