Cell differentiation and flagellar elongation in Naegleria gruberi. Dependence on transcription and translation.
Cell differentiation and flagellar elongation in Naegleria gruberi. Dependence on transcription and translation.
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DOI：
10.1083/jcb.85.2.346
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发表时间：
1980-05
期刊：
影响因子：
--
通讯作者：
Walsh C
中科院分区：
文献类型：
--
作者：
Fulton C;Walsh C
本文提出的证据表明，发生时，细胞被放置在一个无营养的水环境中的表型转化的Naegleria gruberi从阿米巴到鞭毛虫是依赖于转录和翻译。RNA和蛋白质在一小时的分化过程中合成。在分化所需的整个时间内，放线菌素D和道诺霉素选择性抑制RNA合成，放线菌酮选择性抑制蛋白质合成。如果在细胞转移到非营养缓冲液后不久加入这些抑制剂，则可防止分化，但在随后的可重复时间（过渡点）停止阻断特定分化事件。在每个转变点之后，形态发生可以在抑制剂存在下并且在转录或翻译的虚拟缺失下发生。转换点的地图表明，RNA合成是必需的，直到一半的时间过程从启动到鞭毛组装，蛋白质合成是必需的，直到四分之三的方式通过。甚至当鞭毛生长可以发生在放线菌酮的存在下，形成的鞭毛的长度是由一个未知的“限制前体的合成程度决定的。“鞭毛形成和流线型鞭毛虫体形状形成的过渡点在时间上是分开的。这些结果表明，耐格里属的分化涉及细胞代谢的重定向，以产生新的RNA和蛋白质分子，这是形态发生所必需的。
This paper presents evidence that the phenotypic transformation of Naegleria gruberi from amebae to flagellates that occurs when cells are placed in a nutrient-free aqueous environment is dependent on transcription and translation. RNA and protein are synthesized during the hour-long differentiation. Actinomycin D and daunomycin selectively inhibit RNA synthesis, and cycloheximide selectively inhibits protein synthesis, throughout the time required for differentiation. These inhibitors prevent differentiation if added soon after the cells are transferred to nonnutrient buffer but cease to block specific differentiation events at subsequent, reproducible times, the transition points. After each transition point, morphogenesis can occur in the presence of the inhibitor and in the virtual absence of transcription or translation. A map of the transition points indicates that RNA synthesis is required until halfway through the temporal process from initiation to flagellum assembly, and that protein synthesis is required until three-fourths of the way through. Even when flagellum outgrowth can occur in the presence of cycloheximide, the length of the flagella formed is determined by the extent of synthesis of an unknown "limiting precursor." The transition points for formation of flagella and for formation of the streamlined flagellate body shape are temporally separate. These results indicate that differentiation in Naegleria involves a redirection of cell metabolism to produce new RNA and protein molecules that are essential for morphogenesis.