Chiang G G, Schaefer M R, Grossman A R
Department of Plant Biology, Carnegie Institution of Washington, Stanford, CA 94305.
Proc Natl Acad Sci U S A. 1992 Oct 15;89(20):9415-9. doi: 10.1073/pnas.89.20.9415.
Many cyanobacteria alter their phycobilisome composition in response to changes in light wavelength in a process termed complementary chromatic adaptation. Mutant strains FdR1 and FdR2 of the filamentous cyanobacterium Fremyella diplosiphon are characterized by aberrant chromatic adaptation. Instead of adjusting to different wavelengths of light, FdR1 and FdR2 behave as if they are always in green light; they do not respond to red light. We have previously reported complementation of FdR1 by conjugal transfer of a wild-type genomic library. The complementing DNA has now been localized by genetic analysis to a region on the rescued genomic subclone that contains a gene designated rcaC. This region of DNA is also able to complement FdR2. Southern blot analysis of genomic DNA from FdR1 and FdR2 indicates that these strains harbor DNA insertions within the rcaC sequence that may have resulted from the activity of transposable genetic elements. The predicted amino acid sequence of RcaC shares strong identity to response regulators of bacterial two-component regulatory systems. This relationship is discussed in the context of the signal-transduction pathway mediating regulation of genes encoding phycobilisome polypeptides during chromatic adaptation.
许多蓝细菌会在一个被称为互补色适应的过程中，响应光波长的变化来改变其藻胆体组成。丝状蓝细菌双岐颤藻（Fremyella diplosiphon）的突变株FdR1和FdR2具有异常的色适应特征。FdR1和FdR2不是适应不同波长的光，而是表现得好像它们一直处于绿光下；它们对红光没有反应。我们之前报道过通过野生型基因组文库的接合转移对FdR1进行互补。现在通过遗传分析已将互补DNA定位到获救基因组亚克隆上的一个区域，该区域包含一个名为rcaC的基因。这个DNA区域也能够互补FdR2。对FdR1和FdR2基因组DNA的Southern印迹分析表明，这些菌株在rcaC序列内存在DNA插入，这可能是由转座遗传元件的活性导致的。RcaC的预测氨基酸序列与细菌双组分调节系统的响应调节因子具有很强的同源性。在介导色适应过程中编码藻胆体多肽的基因调控的信号转导途径的背景下讨论了这种关系。
