Poster: Photosynthesis
Abs #
376: Genome-wide categorization of photosynthetic and non-photosynthetic genes in Synechocystis PCC 6803 using chlorophyll fluorescence imaging system
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Presenter: |
Sonoike, Kintake , sonoike@k.u-tokyo.ac.jp |
Authors | Sonoike, Kintake (A) Aiba, Hiroshi (A) Fujimori, Tamaki (A) Higuchi, Mieko (A) Ozaki, Hiroshi (A) Ikeuchi, Masahiko (A) Ogawa, Akio (B) Fukuzawa, Hideya (C) Hihara, Yukako (D) | | Affiliations: |
(A): University of Tokyo
(B): Nagoya University
(C): Kyoto University
(D): Saitama University
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| Web Site: | http://www.biol.s.u-tokyo.ac.jp/users/sonoike/lab-e.htm | |
In many photosynthetic and non-photosynthetic organisms, whole genome sequences have been determined, and the functional aspects of each gene on the genomes become a matter of interest. However, the phenotype of each gene-disruptant must be analyzed one by one, so it cannot be easily extended to genome-wide analysis. To solve this problem, we employed chlorophyll fluorescence imaging system as a tool to categorize genes by their function. It was shown that fluorescence kinetics from the photosynthetic pigment, chlorophyll, could be affected by the disruption of non-photosynthetic genes in a cyanobacterium, a photosynthetic prokaryote. Using this technique in the combination with two-dimensional fluorescence imaging system, we screened mutants made by transposon-mediated random insertion. We prepared 579 mutants from genome DNA fragments including about 290 ORFs. As a result, 15 mutants showed different fluorescence kinetics compared with the wild-type cells, and they were classified into 6 groups according to the fluorescence kinetics. Sequencing of the transposon insertion site revealed that 7 different ORFs were destroyed by the transposon insertion. When transposon was inserted in the same ORF, the mutants were categorized into same fluorescence group irrespective of the insertion point within the ORF. Thus, it was confirmed that the change in the fluorescence kinetics reflects the loss of the function of each gene. We can also predict the function of one gene that is categorized in a same group with a well-known gene. It was concluded that the system employed in this work is effective in the prediction of function of unknown genes. Only less than 10% of the genome was examined in our system at present, but we are attempting to extend the survey to whole genome.
