RNA polymerase II elongation complexes paused after the synthesis of 15- or 35-base transcripts have different structures.
RNA polymerase II elongation complexes paused after the synthesis of 15- or 35-base transcripts have different structures.
复制标题
在合成 15 或 35 碱基转录物后暂停的 RNA 聚合酶 II 延伸复合物具有不同的结构。
DOI：
10.1128/mcb.11.3.1508-1522.1991
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发表时间：
1991
影响因子：
5.3
通讯作者：
Luse,DS
中科院分区：
文献类型：
--
作者：
Linn,SC;Luse,DS
We have purified specific RNA polymerase II elongation intermediates initiated at the adenovirus type 2 major late promoter and paused either 15 or 35 to 36 bases downstream of the transcription initiation site. Transcription was arrested at these two sites by combining modification of the promoter sequence with limitation of appropriate nucleotide concentrations in the in vitro reaction. The resultant complexes were remarkably stable and could be purified away from free DNA and contaminating protein-DNA complexes, without loss of activity, by the use of sucrose gradient sedimentation and low-ionic-strength polyacrylamide gel electrophoresis. The complexes were characterized by both DNase I ando-phenanthroline-copper ion nuclease protection assays. The DNase I footprints revealed that the structures of the 15- and 35- to 36-nucleotide transcription complexes differed from those previously reported for an adenovirus type 2 major late preinitiation complex and a subsequent intermediate formed upon addition of ATP. Furthermore, the 35- to 36-nucleotide complex protected a significantly smaller portion of the template than the 15-nucleotide species and migrated at a slightly higher rate in polyacrylamide gels. These observations suggest that changes in structural organization may continue to occur in transcription complexes which are already committed to elongation.
