COMPLEX SPLICING PATTERNS OF RNAS FROM THE EARLY REGIONS OF ADENOVIRUS-2
COMPLEX SPLICING PATTERNS OF RNAS FROM THE EARLY REGIONS OF ADENOVIRUS-2
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DOI：
10.1016/0022-2836(79)90036-6
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发表时间：
1979-01-01
影响因子：
5.6
通讯作者：
LEWIS, JB
中科院分区：
文献类型：
--
作者：
CHOW, LT;BROKER, TR;LEWIS, JB
在环己亚胺或阿糖胞嘧啶不存在或不存在的情况下，从[人宫颈癌]HeLa细胞感染后不同时间的细胞质中分离到腺病毒血清2型（Ad2） 5个早期区编码的RNA种。转录本由单链Ad2 DNA形成的异双链进行了EM表征。每个早期区域都产生了一个复合RNA物种家族，在删除中间序列后，多达4个保守片段拼接在一起。每个家族的转录本都包含一些相同的序列，但保守片段的长度和位置不同，因此具有不同的剪接模式。它们被映射到腺病毒基因组上，并确定了每个物种的相对丰度。基于成熟细胞质RNA的5”端来自启动子近端DNA序列的指示，对早期区域启动子的图谱坐标进行了改进。单链DNA结合蛋白2区信息的5“先导段在感染过程中发生了变化，表明在早期和晚期使用了不同的启动子。用环己亚胺阻断蛋白质合成可以阻止这种转变。3区的转录在早期受其自身启动子的控制，但在中后期也可能受主要r链晚期启动子的指导。早期看到的3区转录本的内部剪接模式在后期持续存在，但一些分子具有与晚期r-链mRNA共同的5‘’三方先导体。其中一个主要的早期3区转录本包含3个RNA片段，这些片段也存在于纤维RNA的推定加工中间体中，这是一个由早期3区与其启动子分离的晚期信息。一些纤维RNA中的这些额外片段显然反映了在后期对早期RNA剪接信号的识别。从大而复杂的复合RNA结构阵列中，可以推断出许多关于RNA剪接机制的见解。
The RNA species encoded by the 5 early regions of adenovirus serotype 2 (Ad2) were isolated from the cytoplasm of [human cervical carcinoma] HeLa cells at various times after infection either in the absence or in the presence of cycloheximide or cytosine arabinoside. The transcripts were characterized by EM of heteroduplexes formed with single-stranded Ad2 DNA. Each early region gave rise to a family of composite RNA species with up to 4 conserved segments spliced together after the deletion of intervening sequences. Transcripts from each family contained some sequences in common but differed in the lengths and positions of the conserved segments and thus had alternative splicing patterns. They were mapped on the adenovirus genome and the relative abundance of each species was determined. The map coordinates of the early region promoters were refined, based on the indication that the 5'' ends of mature cytoplasmic RNA are derived from promoter-proximal DNA sequences. The 5'' leader segment of the region 2 message for the single-stranded DNA binding protein changed during the course of infection, suggesting the utilization of different promoters at early and late times. The transition was prevented by blocking protein synthesis with cycloheximide. Transcription of region 3 was under the control of its own promoter at early times but could also be directed by the major r-strand late promoter at intermediate to late times. The internal splicing patterns of the region 3 transcripts seen at early times persisted at late times, but some molecules had the 5'' tripartite leaders common to late r-strand mRNA. One of the major early region 3 transcripts contained 3 RNA segments which are also present in a presumptive processing intermediate for the fiber RNA, a late message which is separated from its promoter by early region 3. These extra segments in some fiber RNA apparently reflect the recognition of early RNA splicing signals at late times. From the large, complex arrays of composite RNA structures, numerous insights into the RNA splicing mechanisms were inferred.