Transcriptional Activity of Morphologically Intact Proplastid-Nuclei (Nucleoids) Isolated from Tobacco Cultured Cells
Transcriptional Activity of Morphologically Intact Proplastid-Nuclei (Nucleoids) Isolated from Tobacco Cultured Cells
复制标题
从烟草培养细胞中分离的形态完整的前质体核（类核）的转录活性
DOI：
10.1093/oxfordjournals.pcp.a078151
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发表时间：
1991
影响因子：
4.9
通讯作者：
T. Kuroiwa
中科院分区：
文献类型：
--
作者：
A. Sakai;H. Yamashita;Y. Nemoto;S. Kawano;T. Kuroiwa
从培养的烟草细胞（BY-2系）中分离的形态完整的前质体核（与前质体核同义）的转录活性通过体外转录测定和Southern杂交来检测。在60分钟的孵育过程中，分离的前质体核将每微克DNA约7 pmol的UTP掺入RNA中。这种UTP的掺入被鉴定为依赖于DNA依赖性RNA聚合酶的RNA合成。肝素，一种有效的抑制剂的转录起始，没有抑制作用，这表明在分离的前质体核的转录活性主要是由于链伸长的新生转录本。在合适的条件下，在体外转录测定期间，维持了前质体核的紧密组织的染色质样结构。Southern杂交研究表明，由分离的前质体核在体外产生的转录物的模式是类似的，在裂解的前质体系统中产生的转录物和在活细胞中积累的RNA。因此，使用分离的前质体核进行体外转录测定的系统似乎提供了一种合适的方法来分析质体基因的转录调控与质体核中的结构变化之间的关系。
The transcriptional activity of morphologically intact proplastid-nuclei (synonymous with proplastid-nucleoids) isolated from cultured tobacco cells (line BY-2) was examined by an assay of transcription in vitro and Southern hybridization. The isolated proplastid-nuclei incorporated about 7 pmol of UTP into RNA per microgram of DNA during a 60-min incubation. This incorporation of UTP was identified as synthesis of RNA that was dependent on DNA-dependent RNA polymerase. Heparin, a potent inhibitor of initiation of transcription, had no inhibitory effect, suggesting that the transcriptional activity in the isolated proplastid-nuclei is primarily due to chain elongation of nascent transcripts. The compactly organized, chromatin-like structure of the proplastid-nuclei was maintained during the assay of transcription in vitro under suitable conditions. Southern hybridization studies revealed that the pattern of transcripts generated in vitro by the isolated proplastid-nuclei were similar to that of transcripts produced in a lysed proplastid system and that of RNA accumulated in the living cells. Therefore, the system for the assay of transcription in vitro using isolated proplastid-nuclei seems to provide a suitable method for analyzing the relationship between the transcriptional regulation of plastid genes and the structural changes in plastid-nuclei.