Characterization of a dinoflagellate cryptochrome blue-light receptor with a possible role in circadian control of the cell cycle
Characterization of a dinoflagellate cryptochrome blue-light receptor with a possible role in circadian control of the cell cycle
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DOI：
10.1111/j.1529-8817.2007.00339.x
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发表时间：
2007-06-01
影响因子：
2.9
通讯作者：
Van Dolah, Frances M.
中科院分区：
文献类型：
--
作者：
Brunelle, Stephanie A.;Hazard, E. Starr;Van Dolah, Frances M.
Karenia brevis (C. C. Davis) G. Hansen et Moestrup 是一种导致墨西哥湾赤潮的甲藻。调节其细胞周期的信号通路引起人们的兴趣，因为它们是形成有毒藻华的关键，而有毒藻华会导致大规模海洋动物死亡和人类疾病。短卡伦尼亚表现出分期细胞分裂，其中细胞在相对于光开始的精确时间进入S期。在这里，我们证明昼夜节律是这种行为的基础，并且光质量影响细胞周期进展的速率：在蓝光下，短K. brevis 相对于其在类似强度的白光下的行为更早进入S 期，而在红光下，K. brevis 不受影响。 25,000 个短短杆菌表达序列标签 (EST) 的数据库揭示了几个与隐花色素蓝光受体相似的序列，但没有一个与已知的红光受体相关。我们对短短杆菌隐花色素 (Kb CRY) 进行了表征，并对其三维蛋白质结构进行了建模。光裂解酶/CRY 基因家族的系统发育分析表明，Kb CRY 是隐花色素 DASH (CRY DASH) 进化枝的成员。使用设计用于结合 Kb CRY 内保守肽的抗体进行蛋白质印迹，鉴定出一条类似于 55 kDa 的单条带。免疫定位表明，Kb CRY 与拟南芥中的 CRY DASH 一样，定位于叶绿体。这是甲藻中第一个被表征的蓝光受体。由于 Kb CRY 似乎是唯一表达的蓝光受体，因此它可能是细胞周期昼夜节律夹带的候选者。
Karenia brevis (C. C. Davis) G. Hansen et Moestrup is a dinoflagellate responsible for red tides in the Gulf of Mexico. The signaling pathways regulating its cell cycle are of interest because they are the key to the formation of toxic blooms that cause mass marine animal die-offs and human illness. Karenia brevis displays phased cell division, in which cells enter S phase at precise times relative to the onset of light. Here, we demonstrate that a circadian rhythm underlies this behavior and that light quality affects the rate of cell-cycle progression: in blue light, K. brevis entered the S phase early relative to its behavior in white light of similar intensity, whereas in red light, K. brevis was not affected. A data base of 25,000 K. brevis expressed sequence tags (ESTs) revealed several sequences with similarity to cryptochrome blue-light receptors, but none related to known red-light receptors. We characterized the K. brevis cryptochrome (Kb CRY) and modeled its three-dimensional protein structure. Phylogenetic analysis of the photolyase/CRY gene family showed that Kb CRY is a member of the cryptochrome DASH (CRY DASH) clade. Western blotting with an antibody designed to bind a conserved peptide within Kb CRY identified a single band at similar to 55 kDa. Immunolocalization showed that Kb CRY, like CRY DASH in Arabidopsis, is localized to the chloroplast. This is the first blue-light receptor to be characterized in a dinoflagellate. As the Kb CRY appears to be the only blue-light receptor expressed, it is a likely candidate for circadian entrainment of the cell cycle.