Ciminale V, D'Agostino D M, Zotti L, Chieco-Bianchi L
Institute of Oncology, University of Padova, Italy.
J Acquir Immune Defic Syndr Hum Retrovirol. 1996;13 Suppl 1:S220-7. doi: 10.1097/00042560-199600001-00033.
Human T-cell leukemia/lymphotropic viruses type I and type II (HTLV-I and HTLV-II) are complex human retroviruses showing a similar genetic organization but substantially different biologic and pathogenic properties. As in other complex retroviruses, the 3' portion of the HTLV genome contains the peculiar "X region" comprising several partially overlapping open reading frames (ORFs). To search for a possible basis for the pathogenic differences between the two viruses, a number of studies have been carried out to analyze the coding potential of the X region of HTLV-I and, more recently, of HTLV-II. This review focuses on the coding potential of the HTLV-II X region and presents a comparison with that of HTLV-I. Expression of different ORFs present in the X region may be accessed through two expression strategies: alternative splicing and translation of more than one protein from the same mRNA. Initial analyses of the X region proteins indicate that some differ significantly from their HTLV-I homologues, thus providing possible clues to the understanding of the complex life cycle and pathogenicity of the two viruses.
人类嗜T细胞白血病/淋巴瘤病毒I型和II型（HTLV-I和HTLV-II）是复杂的人类逆转录病毒，它们具有相似的基因结构，但生物学和致病特性却有很大差异。与其他复杂逆转录病毒一样，HTLV基因组的3'部分包含特殊的“X区域”，该区域由几个部分重叠的开放阅读框（ORF）组成。为了寻找这两种病毒致病差异的可能基础，已经开展了多项研究来分析HTLV-I的X区域以及最近HTLV-II的X区域的编码潜力。本综述重点关注HTLV-II X区域的编码潜力，并与HTLV-I的编码潜力进行比较。X区域中不同ORF的表达可以通过两种表达策略实现：可变剪接和从同一mRNA翻译出多种蛋白质。对X区域蛋白质的初步分析表明，其中一些与它们的HTLV-I同源物有显著差异，从而为理解这两种病毒复杂的生命周期和致病性提供了可能的线索。
