Burgyan J, Rubino L, Russo M
Dipartimento di Protezione delle Piante, Università degli Studi, Bari, Italy.
J Gen Virol. 1996 Aug;77 ( Pt 8):1967-74. doi: 10.1099/0022-1317-77-8-1967.
Multivesicular bodies (MVB) are membranous cytoplasmic inclusions that are invariably associated with tombusvirus infections regardless of the virus species, the host, or the tissue examined. MVB are virus-induced structures since they are absent from tissues of healthy plants and are always present both in infected plants and protoplasts. MVB derive from peroxisomes in cells infected by a number of tombusviruses including cymbidium ringspot virus (CymRSV) and from mitochondria in cells infected by another tombusvirus, carnation Italian ringspot virus (CIRV). By using common restriction sites in full-length infectious clones, hybrid clones of these two viruses were constructed. In addition, a mutant of CIRV was prepared in which the protein encoded by the first open reading frame was shortened by 22 amino acids. All mutant transcripts were viable and infected Nicotiana benthamiana plants. Infected leaf tissue samples were collected, processed for thin sectioning, and observed in the electron microscope. The origin of MVB was shown to be under the control of the 5' region of the viral genome. A sequence as short as about 600 nucleotides in ORF 1 contained the determinants for formation of MVB from peroxisomes or mitochondria.
多泡体（MVB）是膜性细胞质内含物，无论病毒种类、宿主或所检查的组织如何，它们总是与番茄病毒感染相关。MVB是病毒诱导的结构，因为在健康植物组织中不存在，而在受感染的植物和原生质体中总是存在。MVB来源于多种番茄病毒感染的细胞中的过氧化物酶体，包括大花蕙兰环斑病毒（CymRSV），以及另一种番茄病毒康乃馨意大利环斑病毒（CIRV）感染的细胞中的线粒体。通过使用全长感染性克隆中的共同限制性酶切位点，构建了这两种病毒的杂交克隆。此外，制备了CIRV的一个突变体，其中第一个开放阅读框编码的蛋白质缩短了22个氨基酸。所有突变体转录本均具有活性，并感染了本氏烟草植株。收集受感染的叶片组织样本，进行超薄切片处理，并在电子显微镜下观察。结果表明，MVB的起源受病毒基因组5'区域的控制。开放阅读框1中短至约600个核苷酸的序列包含了过氧化物酶体或线粒体形成MVB的决定因素。
