Transcription and metabolism of RNA from the Drosophila melanogaster heat shock puff site 93D
Transcription and metabolism of RNA from the Drosophila melanogaster heat shock puff site 93D
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果蝇热休克泡芙位点 93D RNA 的转录和代谢
DOI：
10.1007/bf00292683
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发表时间：
2004
期刊：
影响因子：
1.6
通讯作者：
M. Pardue
中科院分区：
文献类型：
--
作者：
J. Lengyel;L. Ransom;M. Graham;M. Pardue
通过与多线染色体制剂和重组DNA杂交，研究了主要热休克泡芙位点93D和从其转录的RNA的特征。通过饱和原位杂交，93 D 处转录区的长度是热激泡芙位点 87 A 处 mRNA 编码区长度的两倍。根据 87 A 处热激 mRNA 序列的已知长度，我们计算出 93 D 处转录区的最小长度为 9.6 kb（kb = 千碱基，即 1,000 个核苷酸）。 — 将 93 D 转录的 RNA 代谢与在 35° C 温育一小时的细胞中编码主要热休克蛋白 hsp70 的 RNA 代谢进行了比较。通过与特定重组 DNA 探针杂交和与 87 A 原位杂交进行测定，在聚 (A)+ 和聚 (A)− 细胞质 RNA 中发现了 Hsp70 mRNA 序列，并且在细胞质 RNA 中比在核 RNA 中更集中。相反，通过原位杂交测定，与 93 D 互补的序列更集中在核中，而不是在细胞质 RNA 中。这意味着，与来自 87 A 的序列相比，来自 93 D 的序列以较低的速率从细胞核退出和/或以较高的速率在细胞质中翻转。位点 93 D 也很不寻常，因为它的转录区域同时出现在聚 (A)+ 和聚 (A)− 核 RNA 中，尽管细胞质中的 93 D-互补 RNA 主要是聚 (A)−。最后，在 93 D 转录的 DNA 长度中只有 28-58% 存在于细胞质 RNA 中，这表明只有一部分从 93 D 转录的序列从细胞核中输出。因此，来自两个热休克基因座 93 D 和 87 A 的转录物似乎以显着不同的方式代谢。
Characteristics of the major heat shock puff site 93 D and the RNA transcribed from it have been investigated by hybridization to polytene chromosome preparations and to recombinant DNA. By saturation in situ hybridization, the length of the transcribed region at 93 D is twice that of the mRNA coding region at the heat shock puff site 87 A. From the known length of the heat shock mRNA sequence at 87 A, we calculate that the minimum length of the transcribed region at 93 D is 9.6 kb (kb = kilobase, i.e., 1,000 nucleotides). — The metabolism of RNA transcribed from 93 D has been compared with that of RNA coding for the major heat shock protein hsp70 in cells incubated for one hour at 35° C. Hsp70 mRNA sequences, assayed by hybridization to a specific recombinant DNA probe and by in situ hybridization to 87 A, were found in both poly(A)+ and poly(A)− cytoplasmic RNA and were more concentrated in cytoplasmic RNA than in nuclear RNA. In contrast, sequences complementary to 93 D, assayed by in situ hybridization, were more concentrated in nuclear than in cytoplasmic RNA. This implies that sequences from 93 D exit from the nucleus at a lower rate and/or are turned over in the cytoplasm at a higher rate, than sequences from 87 A. Site 93 D is also unusual in that its transcribed region is represented in both poly (A)+ and poly (A)− nuclear RNA, even though 93 D-complementary RNA in the cytoplasm is predominantly poly (A)−. Finally, only 28–58% of the length of DNA transcribed at 93 D is represented in cytoplasmic RNA, indicating that only a portion of the sequences transcribed from 93 D are exported from the nucleus. The transcripts from two heat shock loci, 93 D and 87 A, thus appear to be metabolized in significantly different ways.