Abstract
Cyanobacteria have several phytochrome(-like) genes, and some of which were suggested to be the photoreceptor of phototaxis.
In 2002,whole genome sequence of Thermosynechococcus elongatus BP-1 was opened to the public. In the database,5 ORFs(tll0569,tll0899,tlr0911,tlr0924,tlr1999) are described as phytochrome-like genes. The tll0569 gene was very similar to pixJ1(sll0041),which was proposed to be photoreceptor gene for phototaxis in Synechocystis sp. PCC6803. It formed a gene cluster,like the pixJ1 gene. By immunogold labeling of Tll0569 protein,it was primarily localized in both ends of rod-shaped cell.
In the present study,we will report the physiological role of tll0569 gene,especially the putative function as a photoreceptor. The tll0569 gene was expressed in E.coli as a holoprotein with phycocyanobilin. Absorption spectrum of this holoprotein was determined. The action spectrum of the pototaxis in the tll0569 disruptant was measured. Furthermore,we will discuss the role of other phytochrome-like genes.
