Basler C F, Horwitz M S
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Virology. 1996 Jan 15;215(2):165-77. doi: 10.1006/viro.1996.0019.
Adenovirus type 35 (Ad35) is a member of Ad subgroup B, DNA homology cluster B2. The B2 Ads are unique in that they are isolated most frequently from immunosuppressed individuals such as AIDS patients and bone marrow transplant recipients and in that they have a tropism for the urinary tract. One region of the Ad genome which may influence serotype specific pathology is early region 3 (E3). E3 of subgroup C Ad2 and Ad5 has been shown to encode proteins which counteract the immune response to Ad infection. While a great deal is known about gene expression of the subgroup C Ad E3s, little is known about the E3 gene expression from the subgroup B Ads. Although some E3 open reading frames (ORFs) are shared between subgroups B and C, there are additional ORFs that appear in subgroup B. This paper demonstrates the results of an analysis of gene expression from the Ad35 E3 and describes differences in splicing and polyadenylation between the Ad35 and Ad2 E3s. RT-PCR, cDNA sequencing, RNase protection, 3'RACE, and Northern blotting techniques were utilized to identify, quantify, and determine the structure of six Ad35 E3 mRNAs predicted to encode at least seven proteins. A common intron that is removed during splicing of the subgroup C E3 mRNAs is not removed from Ad35 E3 mRNAs, and only one E3 polyadenylation signal is present in the Ad35 E3 while two polyadenylation signals are used in the formation only one E3 polyadenylation signal is present in the Ad35 E3 while two polyadenylation signals are used in the formation of subgroup C E3 mRNAs. The quantity of individual mRNAs encoding homologous proteins for Ad35 and Ad2 also differ substantially, presumably because of the absence in Ad35 of cis-acting signals which have been shown to be important for regulation of Ad2 E3 pre-mRNA processing. Such information should contribute to an understanding of the role the E3 plays in determining subgroup B Ad pathogenesis in general and Ad35 pathogenesis in particular.
35型腺病毒（Ad35）是B亚组腺病毒的成员，属于DNA同源性簇B2。B2亚组腺病毒的独特之处在于，它们最常从免疫抑制个体（如艾滋病患者和骨髓移植受者）中分离出来，并且具有尿道嗜性。腺病毒基因组中一个可能影响血清型特异性病理学的区域是早期区域3（E3）。C亚组Ad2和Ad5的E3已被证明可编码对抗腺病毒感染免疫反应的蛋白质。虽然对C亚组腺病毒E3的基因表达了解很多，但对B亚组腺病毒的E3基因表达知之甚少。尽管B亚组和C亚组之间共享一些E3开放阅读框（ORF），但B亚组中还出现了其他ORF。本文展示了对Ad35 E3基因表达的分析结果，并描述了Ad35和Ad2 E3在剪接和聚腺苷酸化方面的差异。利用逆转录-聚合酶链反应（RT-PCR）、cDNA测序、核糖核酸酶保护、3'端快速扩增cDNA末端（3'RACE）和Northern印迹技术来鉴定、定量并确定六种预测可编码至少七种蛋白质的Ad35 E3 mRNA的结构。在C亚组E3 mRNA剪接过程中去除的一个常见内含子在Ad35 E3 mRNA中未被去除，并且Ad35 E3中仅存在一个E3聚腺苷酸化信号，而在C亚组E3 mRNA形成过程中使用了两个聚腺苷酸化信号。编码Ad35和Ad2同源蛋白质的各个mRNA的数量也有很大差异，推测是因为Ad35中缺乏已被证明对Ad2 E3前体mRNA加工调控很重要的顺式作用信号。这些信息应有助于理解E3在一般情况下决定B亚组腺病毒发病机制，特别是Ad35发病机制中所起的作用。
