The Function Analysis Of SigL And SRNAs In Bacillus Thuringiensis By Bioinformatics

Bacillus thuringiensis is one of principal industrial bio-pesticides used in agriculture and sanitary insect pest control. During the sporulation, B. thuringiensis can produce numerous insecticidal crystal proteins (ICPs) and assemble them into parasporal crystals. The mechanism of the high expression system of ICPs is received widely attention and research. TheσL encoded by sigL plays a very important role in regulation many metabolic pathways in bacteria. So far, the non-coding RNAs were identified as regulators of gene expression in almost all species, which could play inhibition or activation role at transcription or translation levels. The study of sRNAs in B. thuringiensis is still a state of emptiness.The structure and function of SigL and its bacterial enhancer transcription factor (bEBPs) of B. thuringiensis strain YBT-1520 were analyzed by bioinformatics methods, the types and functions of sRNAs in B. thuringiensis strains YBT-1520 and BMB171 were analyzed. The main results obtained are as follows:1) Structure and function analysis of SigL and its bEBPs of B. thuringiensis strain YBT-1520The results indicated that there are only one SigL and six bEBPs in B. thuringiensis strain YBT-1520 genome, respectively. Furthermore, the bEBPs displayed rich structural diversity and possessed all organization types of bEBPs domains. The genes regulated by SigL are related with 11 putative COG metabolism pathways, including energy metabolism, amino acid metabolism, translation and cell cycle, etc. According to the locations of bEBPs in YBT-1520 genome, some bEBPs were predicted to regulate the metabolism pathways of y-aminobutyric acid, arginine, polysaccharide as well as the degradation of branched chain fatty acid.2) Verification of the interactions between bEBPs and PspAs in B. thuringiensis strain YBT-1520Bacterial two-hybrid method was used to research the relationship of bEBPs and PspAs in B. thuringiensis strain YBT-1520. Among the two bEBPs and two PspAs, BtGL001560 has a quite strong interaction with BtGL000962, while the interactions between other partners are either week or unclear. The results suggest that the interactions between bEBPs and PspA s in YBT-1520 should be more complicated and therefore the regulation relations of PspA and PspF in YBT-1520 should be different from those in E. coli. 3) Prediction and analysis of sRNAs in B. thuringiensis YBT-1520 and BMB171 genomesIn B. thuringiensis strain YBT-1520 genome, total 575 sRNAs have been predicted, including 18 rRNAs or tRNAs,441 trans-encoded antisence RNAs,26 known riboswitches and other 90 unknown riboswitches. The results of function cluster analysis of downstream genes showed that the functions of these putative riboswitches were closely related with many important metabolic pathways.In BMB171 genome,576 sRNAs have been predicted, containning 30 rRNAs and tRNAs,402 trans-encoded antisence RNAs,25 known riboswitches and 119 unknown riboswitches. These 119 putative riboswitches may related to 18 COG functional groups, such as signal transduction, cell membrane formation, protein post-translational modification, transport, carbon metabolism, energy metabolism, lipid metabolism and so on.In conclusion, the structure and function of SigL and sRNAs of B. thuringiensis were analyzed through bioinformatics methods and experimental verification. Determination the function of SigL and sRNAs will promote the studies on the metabolism regulations for substance and energy during sporulation and crystallization in B. thuringiensis.