title: Whole genome sequencing reveals a novel CRISPR system in industrial Clostridium acetobutylicum.
abstract: Clostridium acetobutylicum is an important organism for biobutanol production. Due to frequent exposure to bacteriophages during fermentation, industrial C. acetobutylicum strains require a strong immune response against foreign genetic invaders. In the present study, a novel CRISPR system was reported in a C. acetobutylicum GXAS18-1 strain by whole genome sequencing, and several specific characteristics of the CRISPR system were revealed as follows: (1) multiple CRISPR loci were confirmed within the whole bacterial genome, while only one cluster of CRISPR-associated genes (Cas) was found in the current strain; (2) similar leader sequences at the 5' end of the multiple CRISPR loci were identified as promoter elements by promoter prediction, suggesting that these CRISPR loci were under the control of the same transcriptional factor; (3) homology analysis indicated that the present Cas genes shared only low sequence similarity with the published Cas families; and (4) concerning gene similarity and gene cluster order, these Cas genes belonged to the csm family and originated from the euryarchaeota by horizontal gene transfer.
authors.affiliation: State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Guangxi Key Laboratory of Biorefinery, Nanning, Guangxi, 530007, People's Republic of China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Peng
authors.forename: Jianxin
authors.initials: J
authors.lastname: Pei
authors.forename: Hao
authors.initials: H
authors.lastname: Pang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Guo
authors.forename: Lihua
authors.initials: L
authors.lastname: Lin
authors.forename: Ribo
authors.initials: R
authors.lastname: Huang
mesh_terms: D064113:CRISPR-Cas Systems; D046969:Clostridium acetobutylicum / Q000235:genetics*; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D016680:Genome, Bacterial; D007218:Industrial Microbiology; D005810:Multigene Family; D017422:Sequence Analysis, DNA