Interaction of topoisomerase 1 with the transcribed region of the Drosophila HSP 70 heat shock gene.
Interaction of topoisomerase 1 with the transcribed region of the Drosophila HSP 70 heat shock gene.
复制标题
拓扑异构酶 1 与果蝇 HSP 70 热休克基因转录区域的相互作用。
DOI：
10.1093/nar/17.21.8495
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发表时间：
1989
影响因子：
14.9
通讯作者：
Rowe,TC
中科院分区：
文献类型：
--
作者：
Kroeger,PE;Rowe,TC
用喜树碱在果蝇细胞热休克基因Hsp 70上定位了拓扑异构酶I切割位点。拓扑异构酶I切割时，只有观察到热休克蛋白70基因的转录活性。拓扑异构酶I的位点特异性单链DNA切割仅限于Hsp 70基因的转录区域，并且发生在转录和非转录的DNA链上。互补DNA链上的许多单链断裂发生在非常接近的位置，导致双链DNA断裂。用放线菌素D（ActD）或5，6-二氯-1-β-D-呋喃核糖基苯并咪唑（DRB）抑制热诱导的Hsp 70转录，除了在基因的5′端和在较小程度上的3′端外，都抑制了拓扑异构酶I的切割。喜树碱（100 μM）抑制Hsp 70基因的转录大于95%。这些结果表明，拓扑异构酶I是密切相关的，并在热休克蛋白70基因转录的一个组成部分。
Topoisomerase I cleavage sites have been mappedin vivoon the Hsp70 heat shock gene ofDrosophila melanogastercells using the drug camptothecin. Topoisomerase I cleavage was only observed when the Hsp70 gene was transcriptionally active. Site-specific single-strand DNA cleavage by topoisomerase I was confined to the transcribed region of the Hsp70 gene and occurred on both the transcribed and nontranscribed DNA strands. A number of the single-strand breaks on the complementary DNA strands occurred in close proximity giving rise to double-stranded DNA breaks. Inhibition of heat-induced Hsp70 transcription by either Actinomycin D (Act D) or 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB) inhibited topoisomerase I cleavage except at the 5′ and to a lesser extent the 3′ end of the gene. Camptothecin (100 μM) inhibited transcription of the Hsp70 gene greater than 95%. These results suggest that topoisomerase I is intimately associated with and has an integral part in Hsp70 gene transcription.