IGEM:Harvard/2006/Brainstorming Papers - Zhipeng: Difference between revisions
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===Kondo et al.=== | ===Kondo et al.=== | ||
[[Image:Kondo_img.jpg|thumb|Circadian organization (Kondo et al 2004).]] | |||
*gene cluster KaiABC involved | *gene cluster KaiABC involved | ||
*'''no homology to eukarayotic circadian systems''' | *'''no homology to eukarayotic circadian systems''' | ||
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**Overexpression of KaiA activates KaiBC | **Overexpression of KaiA activates KaiBC | ||
**KaiC center of oscillation | **KaiC center of oscillation | ||
*Question TBA: why 24h period? | *Question TBA: why 24h period? | ||
**Single point mutations in KaiC can change period from 14h to 60h | **Single point mutations in KaiC can change period from 14h to 60h |
Latest revision as of 12:55, 16 June 2006
Cyanobacteria
- Kondo T and Ishiura M. The circadian clock of cyanobacteria. Bioessays. 2000 Jan;22(1):10-5. DOI:10.1002/(SICI)1521-1878(200001)22:1<10::AID-BIES4>3.0.CO;2-A |
- Kucho K, Okamoto K, Tsuchiya Y, Nomura S, Nango M, Kanehisa M, and Ishiura M. Global analysis of circadian expression in the cyanobacterium Synechocystis sp. strain PCC 6803. J Bacteriol. 2005 Mar;187(6):2190-9. DOI:10.1128/JB.187.6.2190-2199.2005 |
- Takigawa-Imamura H and Mochizuki A. Transcriptional autoregulation by phosphorylated and non-phosphorylated KaiC in cyanobacterial circadian rhythms. J Theor Biol. 2006 Jul 21;241(2):178-92. DOI:10.1016/j.jtbi.2005.11.013 |
- Kutsuna S, Nakahira Y, Katayama M, Ishiura M, and Kondo T. Transcriptional regulation of the circadian clock operon kaiBC by upstream regions in cyanobacteria. Mol Microbiol. 2005 Sep;57(5):1474-84. DOI:10.1111/j.1365-2958.2005.04781.x |
Kondo et al.
- gene cluster KaiABC involved
- no homology to eukarayotic circadian systems
- Central oscillator controls output patterns; phase of oscillator controlled by input
- Photosynthesis by day, nitrogen fixation by night (2 incompatible in unicellular)
- Used luciferase DNA expressed downstream as a reporter
- Genome 2.7kb in size (e. coli 6.1kb)
- Put luxAB on a psbA plasmid, luxAB luciferase related protein volatile
- See diagram in paper for circuitry
- KaiABC system
- Overexpression of KaiC represses KaiA and KaiB
- Overexpression of KaiA activates KaiBC
- KaiC center of oscillation
- Question TBA: why 24h period?
- Single point mutations in KaiC can change period from 14h to 60h
- Drosophila and Neurospora also have clock models
- Cyanobacteria has no nuclear envelope, can divide 6h/time
- KaiABC analogues only found on archaeobacteria
Kucho et al.
- Purpose of regulation to prepare cell for night in cyanobacteria
- Tested Synechocystis, which is a different strain of cyanobacteria
- 77% in Synechocystis rhymic clones; 100% in Synechococcus
- In cyanobacteria
- KaiC regulated by negative feedback autoreg. loop
- KaiA activates kaiBC
- Used DNA microarray to determine mRNA cyclic nature
- cycling genes detected; peak expression from day to night
- Genes mostly:
- unassigned
- carbohydrate metabolism
- energy metabolism purposes
- transcription!
- translation!
- Genes mostly:
- 2 Sigma factors have circadian rhythm: sll1689, sll0687 on RNAPol
Other
- (Wikipedia)Cyanobacteria are the only group of organisms that are able to reduce nitrogen and carbon in aerobic conditions