title: Three cellulosomal xylanase genes in Clostridium thermocellum are regulated by both vegetative SigA (σ(A)) and alternative SigI6 (σ(I6)) factors.
abstract: Clostridium thermocellum efficiently degrades crystalline cellulose by a high molecular weight protein complex, the cellulosome. The bacterium regulates its cellulosomal genes using a unique extracellular biomass-sensing mechanism that involves alternative sigma factors and extracellular carbohydrate-binding modules attached to intracellular anti-sigma domains. In this study, we identified three cellulosomal xylanase genes that are regulated by the σ(I6)/RsgI6 system by utilizing sigI6 and rsgI6 knockout mutants together with primer extension analysis. Our results indicate that cellulosomal genes are expressed from both alternative σ(I6) and σ(A) vegetative promoters.
authors: Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors: Andy
authors: A
authors: Sand
authors: Thayer School of Engineering at Dartmouth College, Hanover, NH 03755, United States.
authors: Evert K
authors: EK
authors: Holwerda
authors: Thayer School of Engineering at Dartmouth College, Hanover, NH 03755, United States.
authors: Natalie M
authors: NM
authors: Ruppertsberger
authors: Thayer School of Engineering at Dartmouth College, Hanover, NH 03755, United States.
authors: Marybeth
authors: M
authors: Maloney
authors: Thayer School of Engineering at Dartmouth College, Hanover, NH 03755, United States.
authors: Daniel G
authors: DG
authors: Olson
authors: Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors: Yakir
authors: Y
authors: Nataf
authors: Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Ramat Aviv 69978, Israel.
authors: Ilya
authors: I
authors: Borovok
authors: Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, United States.
authors: Abraham L
authors: AL
authors: Sonenshein
authors: Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors: Edward A
authors: EA
authors: Bayer
authors: Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Ramat Aviv 69978, Israel.
authors: Raphael
authors: R
authors: Lamed
authors: Thayer School of Engineering at Dartmouth College, Hanover, NH 03755, United States.
authors: Lee R
authors: LR
authors: Lynd
authors: Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel. Electronic address: yshoham@tx.technion.ac.il.
authors: Yuval
authors: Y
authors: Shoham
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002482:Cellulose / Q000378:metabolism; D044603:Cellulosomes / Q000201:enzymology / Q000235:genetics*; D048013:Acetivibrio thermocellus / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D009154:Mutation; D008897:Panicum / Q000378:metabolism / Q000382:microbiology; D011134:Polysaccharides / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism; D024363:Transcription Initiation Site; D014990:Xylans / Q000378:metabolism; D014995:Xylosidases / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011134:Polysaccharides; D012808:Sigma Factor; D014990:Xylans; C007916:hemicellulose; D002482:Cellulose; D014995:Xylosidases
keywords: Alternative sigma factor; Anti-sigma factor; Biomass sensing; Cellulosome; Clostridium thermocellum; Regulation; Xylanase