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Department of Biological Sciences
Molecular Neuroscience
Developmental Biology
Cellular Genetics
Molecular Genetics
Plant Development and Physiology
Cellular Biochemistry
Evolutionary Genetics
Plant Environmental Responses
Environmental Microbiology
Animal Ecology
Plant Ecology
Systematic Zoology
Systematic Botany
Photo Molecular Genetics Laboratory
Prof Shigeki Ehira e-mail
Asc Prof Ryudo Ohbayashi e-mail
Regulatory network of cellular differentiation in cyanobacteria
Cyanobacteria are a large and morphologically diverse group of phototrophic prokaryotes with wide ecological tolerance that they occur in almost every habitat on earth. Some cyanobacteria can use not only CO2 as a carbon source by photosynthesis, but also N2 as a nitrogen source by nitrogen fixation. Filamentous cyanobacteria, such as Anabaena sp. strain PCC 7120, form differentiated cells called heterocysts, which are specialized cells for nitrogen fixation. Upon limitation of combined nitrogen in the medium, particular vegetative cells within linear multicellular filaments differentiate into heterocysts with a regular spacing of 10-15 cells. Heterocyst differentiation takes about 24 h to complete, when approximately 10% of chromosomal genes are upregulated with spatiotemporal regulation. We are analysing the molecular mechanisms of cellular differentiation and pattern formation using cyanobacteria.
Recent Publications
  1. Kimura, S., Sato, M., Fan, X., Ohmori, M., Ehira, S.* (2022) The two-component response regulator OrrA confers dehydration tolerance through regulation of the expression of avaKa in the cyanobacterium Anabaena sp. strain PCC 7120. Environ. Microbiol. 24: 5165-5173.
  2. Nagao, R.*, Yokono, M., Ueno, Y., Nakajima, Y., Suzuki, T., Kato, K-H., Tsuboshita, N., Dohmae, N., Shen, J-R., Ehira, S.*, Akimoto, S.* (2022) Excitation-energy transfer in heterocysts isolated from the cyanobacterium Anabaena sp. PCC 7120 as studied by time-resolved fluorescence spectroscopy. Biochim. Biophys. Acta Bioenerg. 1863:148509.
  3. Nagao, R.*, Yokono, M., Ueno, Y., Suzuki, T., Kato, K., Kato, K-H., Tsuboshita, N., Jiang, Y-Y., Dohmae, N., Shen, J-R., Ehira, S.*, Akimoto, S.* (2021) Molecular organizations and function of iron-stress-induced-A protein family in Anabaena sp. PCC 7120. Biochim. Biophys. Acta Bioenerg. 1862:148327
  4. Kurio, Y., Koike, Y., Kanesaki, Y., Watanabe, S., Ehira, S.* (2020) The CRP-family transcriptional regulator DevH regulates expression of heterocyst-specific genes at the later stage of differentiation in the cyanobacterium Anabaena sp. strain PCC 7120. Mol. Microbiol. 114:553-562.
  5. Koike, R., Kato, Y., Ehira, S.* (2020) Identification of a gene regulated by HetR, a master regulator of heterocyst differentiation, in the non-heterocyst-forming filamentous cyanobacterium Arthrospira platensis NIES-39. J. Gen. Appl. Microbiol. 66:93-98.
  6. Higo, A., Nishiyama, E., Nakamura, K., Hihara, Y., Ehira, S.* (2019) cyAbrB transcriptional regulators as safety devices to inhibit heterocyst differentiation in Anabaena. J. Bacteriol. 201:e00244-19.
  7. Higo, A., Ehira, S.* (2019) Spatio-temporal gene repression system in the heterocyst-forming multicellular cyanobacterium Anabaena sp. PCC 7120. ACS Synth. Biol. 8:641-646.
  8. Higo, A., Ehira, S.* (2019) Anaerobic butanol production driven by oxygen-evolving photosynthesis using the heterocyst-forming multicellular cyanobacterium Anabaena sp. PCC 7120. Appl. Microbiol. Biotechnol. 103:2441–2447.
  9. Fukushima, S., Ehira, S.* (2018) The Ser/Thr kinase PknH is essential for maintaining of heterocyst pattern in the cyanobacterium Anabaena sp. strain PCC 7120. Life 8:34.
  10. Shimmori, Y., Kanesaki, Y., Nozawa, M., Yoshikawa, H., Ehira, S.* (2018) Transcriptional activation of glycogen catabolism and the oxidative pentose phosphate pathway by NrrA facilitates cell survival under nitrogen starvation in the cyanobacterium Synechococcus sp. strain PCC 7002. Plant Cell Physiol. 59:1225-1233.
  11. Ehira, S.*, Takeuchi, T, Higo, A. (2018) Spatial separation of photosynthesis and ethanol production by cell type-specific metabolic engineering of filamentous cyanobacteria. Appl. Microbiol. Biotechnol. 102:1523-1531.
  12. Ehira, S.*, Shimmori, Y., Watanabe, S., Kato, H., Yoshikawa, H., Ohmori, M. (2017) The nitrogen-regulated response regulator NrrA is a conserved regulator of glycogen catabolism in -cyanobacteria. Microbiology 163:1711-1719.
  13. Ehira, S.*, Miyazaki, S. (2015) Regulation of genes involved in heterocyst differentiation in the cyanobacterium Anabaena sp. strain PCC 7120 by a group 2 sigma factor SigC. Life 5:587-603.
  14. Ehira, S.*, Kimura, S., Miyazaki, S., Ohmori, M. (2014) Sucrose synthesis in the nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120 is controlled by the two-component response regulator OrrA. Appl. Environ. Microbiol. 80:5672-5679.
  15. Ehira, S.*, Ohmori, M. (2014) NrrA directly regulates expression of the fraF gene and antisense RNAs for fraE in the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120. Microbiology 160:844-850.
©2015 Department of Biological Sciences, Tokyo Metropolitan University