The biogenesis of the cyanellae of Cyanophora paradoxa. - II. Pulse-labelling of cyanellar polypeptides in the presence of transcriptional and translational inhibitors
The biogenesis of the cyanellae of Cyanophora paradoxa. - II. Pulse-labelling of cyanellar polypeptides in the presence of transcriptional and translational inhibitors
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Cyanophora paradoxa 蓝藻的生物发生。
DOI：
10.1098/rspb.1989.0067
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
R. Trench
中科院分区：
文献类型：
--
作者：
R. Burnap;R. Trench
放线菌酮和氯霉素，特异性抑制蛋白质翻译的细胞质和蓝腔室，分别，蓝藻，已采用30分钟的脉冲标记实验，通过使用[NaH-14 C]O3在体内标记总细胞蛋白。从宿主细胞裂解物中纯化的蓝藻被分离成可溶性和类囊体组分，并通过一维和二维聚丙烯酰胺凝胶电泳（PAGE）进行分析，以确定在蓝藻多肽的放射性分布。对蓝球藻蛋白质的放射自显影分析表明，在对照中观察到的蓝球藻蛋白质总数的约70%是在胞质核糖体上合成的。大多数（81%）的可溶性蓝藻蛋白质似乎是细胞质合成。相比之下，大多数（70%）的类囊体蛋白是在蓝藻中合成的。观察结果还表明，在蓝藻中合成的多肽包括最丰富和快速转化的物种。先前鉴定的许多多肽现在已经就其合成位点进行了表征。此外，我们报告的标签实验涉及利福平，一种特异性的抑制剂的蓝藻转录，这表明不同的mRNA内的蓝藻有显着不同的稳定性。
Cycloheximide and chloroamphenicol, specific inhibitors of protein translation in the cytoplasmic and cyanellar compartments, respectively, of Cyanophora paradoxa, have been employed in 30 min pulse-labelling experiments by using [NaH-14C]O3 to label total cell proteins in vivo. Cyanellae purified from host cell lysates were separated into soluble and thylakoid fractions and analysed by one- and two-dimensional polyacrylamide gel electrophoresis (PAGE) to determine the distribution of radio-activity in the cyanellar polypeptides. Analysis of the autoradiograms of electrophoretically resolved proteins of the cyanellae indicates that about 70% of the total number of cyanellar proteins visualized in the controls are synthesized on cytoplasmic ribosomes. The majority (81%) of the soluble cyanellar proteins appear to be cytoplasmically synthesized. In contrast, the majority (70%) of the thylakoid proteins are synthesized within the cyanellae. The observations also suggest that the polypeptides synthesized within the cyanellae include species that are the most abundant and rapidly turned over. A number of the polypeptides previously identified have now been characterized with regard to their sites of synthesis. In addition, we report on labelling experiments involving rifampicin, a specific inhibitor of cyanellar transcription, which indicate that different mRNAs within the cyanellae have markedly different stabilities.