Green L L, Dove W F
Mol Cell Biol. 1984 Sep;4(9):1706-11. doi: 10.1128/mcb.4.9.1706-1711.1984.
Physarum myxamoebae can be reversibly induced to become flagellates. Physarum flagellates contain a new form of tubulin, alpha 3, that is not found in nonflagellated cells. Evidence is presented that suggests that alpha 3 tubulin arises through posttranslational modification of a preexisting alpha tubulin. Pulse-chase experiments showed that labeled alpha 3 tubulin could be detected when flagellates formed after a chase. RNA was isolated from myxamoebae at different times after induction of flagellum formation. When this RNA was translated in vitro, the resulting products contained no alpha 3 tubulin, also consistent with alpha 3 being made by posttranslational modification. Levels of alpha and beta tubulin RNA increased with the proportion of flagellates in the culture. These elevated tubulin RNA levels declined after the number of flagellates in the population achieved plateau values.
绒泡菌的变形体可以被可逆地诱导成为鞭毛虫。绒泡菌鞭毛虫含有一种新的微管蛋白形式，α3，在无鞭毛的细胞中未发现。有证据表明，α3微管蛋白是通过对预先存在的α微管蛋白进行翻译后修饰产生的。脉冲追踪实验表明，当鞭毛虫在追踪后形成时，可以检测到标记的α3微管蛋白。在诱导鞭毛形成后的不同时间，从变形体中分离出RNA。当这种RNA在体外翻译时，产生的产物不包含α3微管蛋白，这也与α3是通过翻译后修饰产生的一致。α和β微管蛋白RNA的水平随着培养物中鞭毛虫的比例而增加。在群体中鞭毛虫数量达到稳定值后，这些升高的微管蛋白RNA水平下降。
