Characterization of regulatory regions involved in the inducible expression of chiB in Bacillus thuringiensis
- PDF / 645,086 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 89 Downloads / 186 Views
ORIGINAL PAPER
Characterization of regulatory regions involved in the inducible expression of chiB in Bacillus thuringiensis Chi‑Chu Xie · Jin Shi · Hai‑Yun Jia · Peng‑Fei Li · Yang Luo · Jun Cai · Yue‑Hua Chen
Received: 26 March 2014 / Revised: 13 October 2014 / Accepted: 23 October 2014 / Published online: 2 November 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Expression of the chiB gene from Bacillus thuringiensis Bti75 was defined as inducible by the use of transcriptional fusions with the bgaB reporter gene. The transcription start site of the chiB gene was identified as the C base located 132 base pairs upstream of the start codon. Analysis of 5′ and 3′ deletions of the chiB promoter region revealed that the sequence from position −192 to +36 with respect to the transcription start site was necessary for wild-type levels of inducible expression of the chiB gene. The minimal promoter region for the expression of chiB gene was identified as the sequence from position −100 to +12. Furthermore, a 16-bp sequence (designated dre) downstream of the minimal promoter region of chiB was shown to be required for chitin induction. To confirm the function of this 16-bp sequence, 25 base substitutions were
Communicated by Eriko Takano. C.‑C. Xie · J. Shi · H.‑Y. Jia · P.‑F. Li · Y. Luo · J. Cai · Y.‑H. Chen (*) Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, People’s Republic of China e-mail: [email protected] C.‑C. Xie · J. Shi · H.‑Y. Jia · P.‑F. Li · Y. Luo · J. Cai · Y.‑H. Chen Department of Microbiology, College of Life Sciences, Nankai University, Weijin Road 94, Tianjin 300071, People’s Republic of China Present Address: C.‑C. Xie Department of Immunology, Guiyang Medical College, Guiyang 550004, People’s Republic of China J. Cai · Y.‑H. Chen Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300071, People’s Republic of China
introduced into the dre site. Most of the mutations resulted in constitutive expression, or the efficiency of induction decreased. All mutations identified the dre sequence as a critical site for the inducible expression of chiB. In addition, the dre site was shown to interact with a sequencespecific DNA binding factor of strain Bti75 cultured in the absence of the inducer. Keywords Bacillus thuringiensis · chiB · Genetic elements · Inducible expression
Introduction Chitinases (EC 3.2.1.14), which catalyze the hydrolysis of chitin (a linear homopolysaccharide of N-acetylglucosamine), are potentially useful in industry, medicine and agricultural biological control programs (Khoushab and Yamabhai 2010). A variety of microorganisms produce chitinases, which hydrolyze chitin for use as carbon and energy sources. The expression and application of chitinases in microorganisms has been extensively investigated (Bhattacharya et al. 2007; Babashpour et al. 2012; Chandrasekaran et al. 2012; Purushotham and Podile 2012). Until recently, studies still focused on exploiting the application of chitinases in microorganisms
Data Loading...
