Copine A is expressed in prestalk cells and regulates slug phototaxis and thermotaxis in developing Dictyostelium.
Copine A is expressed in prestalk cells and regulates slug phototaxis and thermotaxis in developing Dictyostelium.
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DOI：
10.1111/j.1440-169x.2011.01300.x
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发表时间：
2011-10
期刊：
影响因子：
--
通讯作者：
Damer CK
中科院分区：
文献类型：
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作者：
Flegel KA;Pineda JM;Smith TS;Laszczyk AM;Price JM;Karasiewicz KM;Damer CK
Copine是在许多真核生物中发现的钙依赖性膜结合蛋白。我们正在使用模式生物Dictyosteelium discoideum研究copines的功能。在饥饿条件下，网囊藻细胞聚集成土丘，成为迁移的蛞蝓，它们可以在最终形成子实体之前向光和热移动。以前，我们表明，缺乏copine A（cpnA）基因的网柄藻细胞不能形成子实体，而是在蛞蝓阶段停止。在这项研究中，我们比较了缺乏cpnA基因的细胞的蛞蝓行为的野生型细胞的蛞蝓行为。由cpnA-细胞形成的蛞蝓比野生型蛞蝓大得多，并且在野生型蛞蝓表现出正趋光性和趋热性的相同条件下表现出无趋光性和负趋热性。将少至5%的野生型细胞与CpnA-细胞混合挽救了趋光性和趋热性缺陷，表明CpnA在调节信号分子的产生和/或释放中起特定作用。降低细胞外氨水平也部分挽救了cpnA-蛞蝓的趋光性和趋热性缺陷，表明CpnA可能在调节氨信号传导中具有特定作用。在野生型细胞中表达lacZ基因的cpnA启动子下，cpnA是优先表达的prestalk细胞中发现的蛞蝓的前部，其中包括细胞在蛞蝓的顶端，调节趋光性，趋热性，并开始到子实体的顶点。我们的研究结果表明，CpnA起着调节信号传导途径，包括氨信号传导，必要的传感和/或定向到光和热的前柄细胞的Dictyosteelium蛞蝓的作用。
Copines are calcium-dependent membrane-binding proteins found in many eukaryotic organisms. We are studying the function of copines using the model organism, Dictyostelium discoideum. When under starvation conditions, Dictyostelium cells aggregate into mounds that become migrating slugs, which can move toward light and heat before culminating into a fruiting body. Previously, we showed that Dictyostelium cells lacking the copine A (cpnA) gene are not able to form fruiting bodies and instead arrest at the slug stage. In this study, we compared the slug behavior of cells lacking the cpnA gene to the slug behavior of wild-type cells. The slugs formed by cpnA- cells were much larger than wild-type slugs and exhibited no phototaxis and negative thermotaxis in the same conditions that wild-type slugs exhibited positive phototaxis and thermotaxis. Mixing as little as 5% wild-type cells with cpnA- cells rescued the phototaxis and thermotaxis defects, suggesting that CpnA plays a specific role in the regulation of the production and/or release of a signaling molecule. Reducing extracellular levels of ammonia also partially rescued the phototaxis and thermotaxis defects of cpnA- slugs, suggesting that CpnA may have a specific role in regulating ammonia signaling. Expressing the lacZ gene under the cpnA promoter in wild-type cells indicated cpnA is preferentially expressed in the prestalk cells found in the anterior part of the slug, which include the cells at the tip of the slug that regulate phototaxis, thermotaxis, and the initiation of culmination into fruiting bodies. Our results suggest that CpnA plays a role in the regulation of the signaling pathways, including ammonia signaling, necessary for sensing and/or orienting toward light and heat in the prestalk cells of the Dictyostelium slug.