2004 Fiscal Year Final Research Report Summary
Comprehensive study on transcriptional network system in the photoautotrophic cyanobacteria Synechococcusstrains
| Project/Area Number |
13206027
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Biological Sciences
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| Research Institution | Nagoya University |
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Principal Investigator |
SUGITA Mamoru Nagoya University, Center for Gene Research, Professor, 遺伝子実験施設, 教授 (70154474)
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| Co-Investigator(Kenkyū-buntansha) |
OMATA Tatsuo Nagoya University, Grad.Sc. Bioagricultural Sciences, Professor, 生命農学研究科, 教授 (50175270)
IWASAKI Hideo Nagoya University, Graduate School of Sciences, Assistant Prof., 理工学術院・電気・情報生命工学科, 助手 (00324393)
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| Project Period (FY) |
2001 – 2004
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| Keywords | cyanobacteria / transcription network / two-component regulatory system / nitrate transport system / DNA chip / photoautotroph / circadian rhythm / clock gene |
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| Research Abstract |
(1) The entire genome of a unicellular cyanobacterium, Synechococcus sp. strain PCC 6301, was sequenced. The genome consisted of a circular chromosome 2,696,255 bp long. A total of 2525 potential protein-encoding genes, two sets of rRNA genes, 45 tRNA genes representing 42 tRNA species and several genes, for small structural RNAs were assigned to the chromosome. Thirty-seven genes for the proteins involved in two-component regulatory system were also annotated. Ten percent of all the protein genes lacked significant similarity to genes for predicted proteins in the public, indicating the genes unique to Synechococcus PCC6301. We constructed high-density DNA microarrays (Affimetrix Gene Chip) of Synechococcus PCC6301 as a tool for comprehensive analysis of transcriptional network in cyanobacteria.
(2) We identified three genes responsible for the latent transport activity for nitrate: ltnA, which encodes a response regulator with no effector domain; ltnB, which encodes a hybrid histidine kinase with two receiver domains; and ltnT, which encodes a sulfate permease-like protein with a putative cyclic nucleoside monophosphate (cNMP)-binding domain.
(3) Circadian clock of cyanobacteria was considered to be composed of negative feedback regulation of kaiBC expression. We demonstrated that KaiC phosphorylation state oscillated even without kaiBC messenger RNA accumulation under continuous dark conditions. Moreover, kinetic profiles in the ratio of KaiC autophosphorylation-dephosphorylation were also temperature compensated in vitro. Thus, the cyanobacterial clock can keep time independent of de novo transcription and translation processes. Furthermore, we have reconstituted the self-sustainable oscillation of KaiC phosphorylation in vitro. The period of the in vitro oscillation was stable and the circadian periods observed in vivo in KaiC mutant strains were consistent with those measured in vitro.
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[Journal Article] Reconstitution of circadian oscillation of cyanobacterial KaiC phosphorylation in vitro.2005
Author(s)
Nakajima, M., Imai, K., Ito, H., Nishiwaki, T., Murayama, Y., Iwasaki, H., Oyama, T., Kondo, T.
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Journal Title
Science 308
Pages: 414-415
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Reconstitution of circadian oscillation of cyanobacterial KaiC phosphorylation in vitro.2005
Author(s)
Nakajima, M., Imai, K., Ito, H., Nishiwaki, T..Murayama, Y., Iwasaki, H., Oyama, T., Kondo, T.
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Journal Title
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Chloroplast phylogeny indicates that bryophytes are monophyletic.2004
Author(s)
Nishiyama, T., Wolf, P.G., Kugita, M., Sinclair, R.B., Sugita, M., et al.
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Journal Title
Molecular Biology and Evolution 21
Pages: 1813-1819
Description
「研究成果報告書概要(和文)」より
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