RNA-TRANSCRIPTION AND SPLICING AT EARLY AND INTERMEDIATE TIMES AFTER ADENOVIRUS-2 INFECTION
RNA-TRANSCRIPTION AND SPLICING AT EARLY AND INTERMEDIATE TIMES AFTER ADENOVIRUS-2 INFECTION
复制标题
DOI：
10.1101/sqb.1980.044.01.044
复制
发表时间：
1979-01-01
期刊：
影响因子：
--
通讯作者：
BROKER, TR
中科院分区：
文献类型：
--
作者：
CHOW, LT;LEWIS, JB;BROKER, TR
人腺病毒2型(Ad2DNA)L的转录通常被认为有一个早期阶段(从感染允许的人类细胞后1-8小时)和一个晚期阶段，基本上与DNA复制相一致(从感染后8小时直到细胞死亡)。溶液杂交研究表明，大约四分之一的基因组在感染后的早期以细胞质RNA的形式表达，这些RNA来自四个完全分离的区域，每条DNA链上两个(Green等人。1971年；夏普等人。1975年；Pettersson等人。1976年)。双链AD2 DNA中由早期AD2 RNA形成的R环的电子显微镜研究(Chow等人1977b；Westphal和Lai 1977)以及RNA-单链DNA异源双链的核酸酶-Sl图谱(Berk和Sharp 1977b)产生的证据表明，早期区域1被细分为两个片段，1a和1b。每个早期区域编码的RNA物种的长度是根据它们在蔗糖梯度离心法或凝胶电泳法中的迁移率来估计的(Craig和Raskas 1976；Biittner等人)。1976年；弗林特1977；斯佩克特等人。1978)以及R-环和核酸酶-S1分析。这些研究揭示了每个早期地区的多个离散大小的类别。其中一些转录本被证明是来自两个或三个不同DNA片段的剪接RNA分子(Kitchingman等人)。1977年；伯克和夏普1978年)。利用对RNA-单链-DNA异源双链的电子显微镜分析，我们扩展了这些研究，以提供感染后不同时间从细胞中分离的AD2早期区域的坐标、剪接模式和相对丰度的详尽表征。还分析了蛋白质合成抑制剂放线菌胺(CH)和DNA合成抑制剂阿糖胞苷(Ara C)的效果(Chow等人。1979年)。在这篇文章中，我们总结了我们最近的观察，这些观察表明AD2染色体对应于5.5 Colicin E1(ColE1)DNA长度相当(Chow等人。1977b)。最近，ColE1DNA的长度已经从6300对修改为6650对(Ohtsubo等人)。1980)。因此，从AD2核苷酸位置到百分比MAP单位的转换是基于36,500个核苷酸的基因组大小。存在一组可被认为代表转录中间阶段的RNA转录本。这些RNA在感染后8小时合成，但在8-16小时达到最高表达。当DNA复制被Ara C抑制时，它们的转录可以发生。我们还将RNA结构与DNA序列和蛋白质产物相关联，并从DNA和RNA序列以及蛋白质大小中推断RNA剪接的许多生物学作用和后果。
Transcription of human adenovirus-2 (Ad2) DNA l has generally been recognized to have an early phase (from 1 to 8 hours after infection of permissive human cells) and a late phase, essentially coincident with DNA replication (from 8 hours until cell death at 48-72 hours after infection). Solution-hybridization studies have shown that about one fourth of the genome is expressed as cytoplasmic RNA at early times after infection and that these RNAs come from four widely separated regions, two on each DNA strand (Green et al. 1971; Sharp et al. 1975; Pettersson et al. 1976). Electron microscopic studies of R loops formed with early Ad2 RNA in double-stranded Ad2 DNA (Chow et al. 1977b; Westphal and Lai 1977) as well as nuclease-Sl mapping of RNA-single-stranded-DNA heteroduplexes (Berk and Sharp 1977b) produced evidence that early region 1 is subdivided into two segments, 1A and lB. The lengths of the RNA species encoded by each early region have been estimated from their mobilities during sucrose gradient centrifugation or gel electrophoresis (Craig and Raskas 1976; Biittner et al. 1976; Flint 1977; Spector et al. 1978) as well as by the R-loop and nuclease-S1 analyses. These studies revealed multiple discrete size classes from each early region. Some of the transcripts were shown to be spliced RNA molecules derived from two or three separate segments of DNA (Kitchingman et al. 1977; Berk and Sharp 1978). Using electron microscopic analysis of RNA-single-stranded-DNA heteroduplexes, we have extended these investigations to provide an exhaustive characterization of the coordinates, splicing patterns, and relative abundances of the cytoplasmic RNA products of the early regions of Ad2 isolated from cells at different times after infection. The effects of cycloheximide (CH), an inhibitor of protein synthesis, and cytosine arabinoside (Ara C), an inhibitor of DNA synthesis, were also analyzed (Chow et al. 1979). In this paper we summarize our recent observations, which suggest the tThe Ad2 chromosome corresponds to 5.5 colicin E1 (ColE1) DNA length equivalents (Chow et al. 1977b). Recently, the length of ColE1 DNA has been revised from 6300 to 6650 nucleotide pairs (Ohtsubo et al. 1980). Therefore, conversions from Ad2 nucleotide positions to percentage map units are based on a genome size of 36,500 nucleotides. existence of a group of RNA transcripts that can be considered to represent an intermediate phase of transcription. These RNAs are synthesized by 8 hours postinfection, but reach maximal expression between 8 and 16 hours. Their transcription can occur when DNA replication is inhibited by Ara C. We also correlate the RNA structures with DNA sequences and protein products and draw inferences from the DNA and RNA sequences and protein sizes about the many biological roles and consequences of RNA splicing.