Coordination of N <sub>2</sub> -fixing cell specialization and patterning in filamentous cyanobacteria by a uniquely structured σ factor
Abstract
Cell differentiation and Turing-like patterning are tightly associated in a group of filamentous cyanobacteria that differentiate specialized N 2 -fixing cells, called heterocysts. Based on systematic genetic analyses, in particular genome-wide identification of recognized promoters and assays with a reconstituted Anabaena transcription system in Escherichia coli , we established HetZ as the central activator of the gene regulatory network of heterocyst differentiation. Biochemical and cryo-EM analyses further established HetZ as a σ factor (σ HetZ ). Unique domain insertions in σ HetZ are involved in promoter DNA recognition-unwinding and interaction with the inhibitor PatU3. σ HetZ -PatU3 and the master regulator-diffusible inhibitor constitute the minimal core regulatory circuit (CRC) for cell fate determination and patterning. σ HetZ activates not only genes of the CRC but also downstream regulator/effector genes involved in morphological and functional development. The gene regulatory network and the structure–function relationship of σ HetZ depict how cell differentiation and patterning are coordinated in this group of multicellular cyanobacteria.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (14)
Xi Hu
Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University
Xujiao Liu
Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences
Yali Wang
The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences
Ke Liu
Hong Gao
Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry
Geqian Zhu
Institute of Hydrobiology, Chinese Academy of Sciences
Shuai Wang
Xiantao Fang
Institute of Hydrobiology, Chinese Academy of Sciences
Hong Sun
Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences
Fang Zhou
Institute of Hydrobiology, Chinese Academy of Sciences
Shuiling Ji
Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University
Congzhao Zhou
School of Life Sciences and Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China
Yu Zhang
Xiangya Hospital, Central South University Changsha China
Xudong Xu
Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University