Light-dependent regulation of cyanobacterial phytochrome expression
Light-dependent regulation of cyanobacterial phytochrome expression
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DOI：
10.1128/jb.182.1.38-44.2000
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发表时间：
2000-01-01
影响因子：
3.2
通讯作者：
Florencio, FJ
中科院分区：
文献类型：
--
作者：
García-Domínguez, M;Muro-Pastor, MI;Florencio, FJ
最近在蓝细菌集胞藻（Synechocystis sp）PCC 6803中发现了一种组氨酸激酶蛋白（Cph 1），其序列同源性和光谱特征与植物光敏色素非常相似，Cph 1与响应调节因子CheY的同源蛋白Rcp 1一起构成一个光调节双组分系统，其功能目前尚不清楚。cph 1 rcp 1 mRNA水平在黑暗中增加，在再光照时降低，黑暗介导的cph 1 rcp 1 mRNA水平的增加被葡萄糖的存在抑制，但不被光合电子how的抑制所抑制，cph 1 rcp 1转录物在光照下的半衰期比在黑暗中短约四倍，表明控制CPH1RCP1转录物稳定性是光调节蓝藻光敏色素表达的机制之一。黑暗15分钟后，3分钟脉冲的红色，蓝色，绿色和远红光同样有效地降低cph 1 rcp 1 mRNA水平。远红光不能逆转红光下调，表明cph1 rcp1 mRNA水平不受光敏色素样光感受器的控制。此外，一个集胞藻菌株含有H538R Cph 1点突变，不能磷酸化Rcp1，显示正常的光暗调节的cph 1 rcp1转录水平。我们的数据表明，蓝藻光敏色素在控制过程中所需的适应在光暗和暗光转换的作用。
A histidine kinase protein (Cph1) with sequence homology and spectral characteristics very similar to those of the plant phytochrome has been recently identified in the cyanobacterium Synechocystis sp, strain PCC 6803, Cph1 together with Rcp1 (a protein homologue to the response regulator CheY) forms a light-regulated two-component system whose function is presently unknown. Levels of cph1 rcp1 mRNA increase in the dark and decrease upon reillumination, A dark-mediated increase in cph1 rcp1 mRNA levels was inhibited by the presence of glucose, but not by inhibition of the photosynthetic electron how, The half-life of cph1 rcp1 transcript in the light was about fourfold shorter than in the dark, indicating that control of cph1 rcp1 transcript stability is one of the mechanisms by which light regulates expression of the cyanobacterial phytochrome. After 15 min of darkness, 3-min pulses of red, blue, green, and far-red light were equally efficient in decreasing the cph1 rcp1 mRNA levels. Red light downregulation was not reversed by far-red light, suggesting that cph1 rcp1 mRNA levels are not controlled by a phytochrome-like photoreceptor. Furthermore, a Synechocystis strain containing an H538R Cph1 point mutation, unable to phosphorylate Rcp1, shows normal light-dark regulation of the cph1 rcp1 transcript levels. Our data suggest a role of cyanobacterial phytochrome in the control of processes required for adaptation in light-dark and dark-light transitions.