Circadian rhythms in the thermophilic cyanobacterium Thermosynechococcus elongatus: compensation of period length over a wide temperature range.
Proteins derived from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1, which performs plant-type oxygenic photosynthesis, are suitable for biochemical, biophysical, and X-ray crystallographic studies. We developed an automated bioluminescence real-time monitoring system for the circadian clock in the thermophilic cyanobacterium T. elongatus BP-1 that uses a bacterial luciferase gene set (Xl luxAB) derived from Xenorhabdus luminescens as a bioluminescence reporter gene. A promoter region of the psbA1 gene of T. elongatus was fused to the Xl luxAB gene set and inserted into a specific targeting site in the genome of T. elongatus. The bioluminescence from the cells of the psbA1-reporting strain was measured by an automated monitoring apparatus with photomultiplier tubes. The strain exhibited the circadian rhythms of bioluminescence with a 25-h period length for at least 10 days in constant light and temperature. The rhythms were reset by light-dark cycle, and their period length was almost constant over a wide range of temperatures (30 to 60 degrees C). Theses results indicate that T. elongatus has the circadian clock that is widely temperature compensated.
Onai
Kiyoshi
K
Center for Gene Research, Nagoya University, Furo, Chikusa, Nagoya 464-8602, Japan. ishiura@gene.nagoya-u.ac.jp
Morishita
Megumi
M
Itoh
Shino
S
Okamoto
Kazuhisa
K
Ishiura
Masahiro
M
D001431:Bacteriological Techniques; D002940:Circadian Rhythm / Q000502:physiology*; D000458:Cyanobacteria / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D006358:Hot Temperature; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D019076:Transgenes
D045332:Photosystem II Protein Complex; C422369:photosystem II, psbA subunit; D008156:Luciferases