Translational regulation of polysome formation during dormancy of Physarum polycephalum
Translational regulation of polysome formation during dormancy of Physarum polycephalum
复制标题
多头绒泡菌休眠期间多聚体形成的翻译调控
DOI：
10.1128/jb.140.2.490-497.1979
复制
发表时间：
1979
影响因子：
3.2
通讯作者：
W. Jeffery
中科院分区：
文献类型：
--
作者：
W. Jeffery
通过对多头绒泡菌活跃生长微原质团和休眠微菌核中核糖体在多聚核糖体中的分布进行分析，研究了它们的翻译活性。微原质团后线粒体组分含有大量的多聚核糖体和核糖体亚基，但很少的本地单体。在饥饿期间，微菌核形成之前，多核糖体水平保持不变，而亚基滴度开始增加。在包囊形成过程中，核糖体亚基继续积累，而多核糖体水平逐渐下降。核盘菌微菌核含有大量剩余的核糖体亚基，但没有检测到多核糖体。然而，孵育的微菌核浓度放线菌酮足以减缓多肽的延伸，而不影响启动引起的逐步再现的多聚核糖体的亚基的费用。在这些条件下，驱动进入多聚核糖体的亚基的百分比达到类似于活跃生长的微原质团的值。微菌核回到营养培养基中含有非常低水平的多核糖体在发芽前的滞后期。这些是由预先存在的储存的信使核糖核酸形成的。在萌发期间，多核糖体水平显着增加。这种升高依赖于新的核糖核酸转录。可以得出结论，休眠的微菌核含有功能信使核糖核酸和核糖体，它们在起始水平受到翻译抑制。
The translational activity of actively growing microplasmodia and dormant microsclerotia of Physarum polycephalum was investigated by analyzing the distribution of ribosomes in polysomes. Microplasmodial post-mitochondrial fractions contained substantial amounts of polysomes and ribosomal subunits but very few native monosomes. During the starvation period which preceded microsclerotium formation, polysome levels remained constant, whereas the subunit titer began to increase. During encystment ribosomal subunits continued to accumulate as the level of polysomes gradually decreased. Dormant microsclerotia contained a large surplus of stored ribosomal subunits but no detectable polysomes. However, incubation of microsclerotia with concentrations of cycloheximide sufficient to slow polypeptide elongation without affecting initiation caused the gradual reappearance of polysomes at the expense of the subunits. Under these conditions the percentage of subunits driven into polysomes reached values similar to those of actively growing microplasmodia. Microsclerotia returned to nutrient medium contained very low levels of polysomes during the lag period which preceded germination. These were formed with preexisting, stored messenger ribonucleic acid. During the germination period, polysome levels were markedly increased. This elevation was dependent on new ribonucleic acid transcription. It is concluded that dormant microsclerotia contain functional messenger ribonucleic acid and ribosomes which are subject to translational repression at the level of initiation.