FLAGELLAR TIP ACTIVATION STIMULATED BY MEMBRANE ADHESIONS IN CHLAMYDOMONAS GAMETES
FLAGELLAR TIP ACTIVATION STIMULATED BY MEMBRANE ADHESIONS IN CHLAMYDOMONAS GAMETES
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DOI：
10.1083/jcb.84.3.599
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发表时间：
1980-01-01
影响因子：
7.8
通讯作者：
GOODENOUGH, UW
中科院分区：
文献类型：
--
作者：
MESLAND, DAM;HOFFMAN, JL;GOODENOUGH, UW
C.交配型正、负配子鞭毛间的膜粘连。reinhardi刺激鞭毛尖端超微结构的快速变化，称为鞭毛尖端激活（FTA）。一种致密的物质，称为纤维尖端材料（FTM），聚集在鞭毛膜和尖端的9个单A微管之间。然后A微管伸长，生长到尖端的远端区域，使尖端长度增加30%。FTA动力学在正常和突变体交配，并提出了实验设计，以探测其在交配反应中的作用。FTA是由交联鞭毛膜成分（包括天然性凝集素，抗鞭毛抗血清，刀豆球蛋白A），但不是由鞭毛粘附聚赖氨酸包被的膜。FTA是由鞭毛脱粘逆转。配子可以在连续的粘附/脱粘循环期间经历FTA的重复循环。自由贸易协定，鞭毛倾斜，性信号被秋水仙碱和长春碱同时阻断，这表明微管蛋白样分子，也许暴露在膜表面，参与所有三种反应。FTA是不阻断短期暴露于糜蛋白酶，细胞松弛素B和D，也不是刀豆球蛋白A，即使所有的块细胞融合，因此，该反应是自主的和实验分离的交配反应的后期阶段。在实验条件下，除非FTA也发生，否则观察到发生配对结构活化。FTA是性信号序列中的一个必要事件，并为其机制提供了一个可检验的工作模型。
Membrane adhesions between the flagella of mating-type plus and minus gametes of C. reinhardi are shown to stimulate a rapid change in the ultrastructure of the flagellar tips, designated as flagellar tip activation (FTA). A dense substance, termed fibrous tip material (FTM), accumulates between the flagellar membrane and the 9 single A microtubules of the tip. The A microtubules then elongate, growing into the distal region of the tip, increasing tip length by 30%. FTA kinetics were described during normal and mutant matings and presents experiments designed to probe its role in the mating reaction. FTA is elicited by agents that cross-link flagellar membrane components (including natural sexual agglutinins, antiflagellar antisera, and concanavalin A) but not by flagellar adherence to polylysine-coated films. FTA is reversed by flagellar disadhesion. Gametes can undergo repeated cycles of FTA during successive rounds of adhesion/disadhesion. FTA, flagellar tipping, and sexual signaling are simultaneously blocked by colchicine and by vinblastine, suggesting that tubulinlike molecules, perhaps exposed at the membrane surface, are involved in all three responses. FTA is not blocked by short exposure to chymotrypsin, by cytochalasins B and D, nor by concanavalin A, even though all block cell fusion; the response is therefore autonomous and experimentally dissociable from later stages in the mating reaction. Under to experimental conditions is mating-structure activation observed to occur unless FTA also occurs. FTA is a necessary event in the sexual signaling sequence, and presents a testable working model for its mechanism.