Heat-Shock Induced Accumulation of Extremely Long Transcripts Containing the rDNA Intergenic Spacer in Arabidopsis
Heat-Shock Induced Accumulation of Extremely Long Transcripts Containing the rDNA Intergenic Spacer in Arabidopsis
复制标题
热激诱导拟南芥中含有 rDNA 基因间隔区的极长转录本的积累
DOI：
10.1093/oxfordjournals.pcp.a078266
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Y. Komeda
中科院分区：
文献类型：
--
作者：
Taku Takahashi;Y. Komeda
从拟南芥核糖体DNA（rDNA）基因间隔区（IGS）中克隆了一个1.2kb的cDNA克隆。在先前的研究中，通过对从热休克的拟南芥幼苗制备的cDNA文库进行差异筛选，实现了该克隆的分离（Takahashi和Komeda 1989）。核苷酸序列分析显示，cDNA具有与IGS中发现的序列相对应的oligo（dA）序列。以克隆的cDNA为探针进行北方印迹分析表明，热激处理诱导了幼苗中表观长度超过7 kb的超长转录本的积累。用亚砷酸盐和镉离子处理也导致RNA的积累，这一现象与在热休克蛋白（HSPs）基因表达的情况下观察到的非常相似。尽管这些转录本可能来自拟南芥rDNA簇外IGS同源区域的可能性仍有待排除，但最有可能的是前体rRNA的加工和/或rRNA转录的终止在植物的胁迫条件下受到极大损害，如在动物rRNA基因的情况下所报道的（Labhart和里德1987，帕克和邦德1989）。
A cDNA clone containing a 1.2-kb fragment derived from the ribosomal DNA (rDNA) intergenic spacer (IGS) ofArabidopsiswas characterized. Isolation of this clone was achieved in a previous study by differential screening of a cDNA library prepared from heat-shockedArabidopsisseedlings (Takahashi and Komeda 1989). Nucleotide sequence analysis revealed that the cDNA had an oligo(dA) sequence that corresponded to the sequence found in the IGS. Northern blot analysis using the cloned cDNA as probe demonstrated that heat-shock treatment of seedlings induced the accumulation of extremely long transcripts with apparent lengths of more than 7 kb. Treatment with arsenite and cadmium ions also led to the accumulation of the RNA, a phenomenon very similar to that observed in the case of expression of genes for heat-shock proteins (HSPs). Although the possibility remains to be excluded that these transcripts might be derived from a region homologous to the IGS located outside the rDNA clusters inArabidopsis, it is most likely that processing of precursor rRNA and/or termination of transcription of rRNA are greatly impaired under stressed conditions in plants, as reported in the case of animal genes for rRNA (Labhart and Reeder 1987, Parker and Bond 1989).