Regulation of expression of photosynthetic genes by the two-component regulatory system of photosynthetic bacteria

1. 克隆了球形红杆菌双组分调控系统下游基因spb、orf5、orf318和ahcy2。Spb是荚膜红杆菌中hvrA的同源物，但其功能与Rba不同。其中spb为光抑制因子，hvrA为光激活因子。orf318是一个与细菌中参与脂多糖合成的糖基转移酶RfaI和RfaJ同源的新基因。在好氧条件下，orf5的破坏导致黑暗中生长速率的抑制。在一种好氧光合细菌——反硝化玫瑰杆菌中，存在类似的基因，包括双组分调控基因，这表明这些细菌对光合基因的调控系统本质上是相同的。结果表明双组分调控基因的下游基因可能参与了信号转导途径。

1. Genes downstream of the two-component regulatory system of Rhodobacter sphaeroides were cloned and they were spb, orf 5, orf 318 and ahcY.2. Spb was a homologue of hvrA in Rhodobacter capsulatus but its function was differed from that of Rba. capsulatus in that spb was light-repressor, whereas hvrA was light-activator3. Orf 318 was a novel gene which had homology with RfaI and RfaJ, which are glycosyltransferases involved in the synthesis of lipopolysaccharide in bacteria.4. Disruption of orf 5 caused inhibition of growth rate in the dark under aerobic conditions.5. In an aerobic photosynthetic bacterium, Roseobacter denitrificans, there existed similar genes including two-component regulatory genes, indicating that the regulatory system for photosynthetic genes was essentially the same in these bacteria.6. The results obtained indicate the possible involvement of genes downstream of the two-component regulatory gene in the signal transduction pathway.