Department of Cell Biology, Kyoto Pharmaceutical University, Misasagi-Shichono-cho 1, Yamashina-ku, Kyoto, 607-8412, Japan.
Sci Rep. 2017 Mar 23;7(1):329. doi: 10.1038/s41598-017-00401-7.
Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. KSHV establishes a life-long infection in its host and alternates between a latent and lytic infection state. During lytic infection, lytic-related genes are expressed in a temporal manner and categorized as immediate early, early, and late gene transcripts. ORF34 is an early-late gene that interacts with several viral transcription-associated factors, however its physiological importance remains poorly understood. Here, we investigated the role of ORF34 during KSHV infection by generating ORF34-deficient KSHV, using a bacterial artificial chromosome system. Our results reveal that ORF34-deficient KSHV exhibited significantly attenuated late gene expression and viral production but did not affect viral DNA replication. ORF34 interacted with transcription factors ORF18, ORF24, ORF31, and ORF66, and a novel ORF34-interaction partner, ORF23. The C-terminal region of ORF34 was important for interaction with ORF24 and viral production. Our data support a model, in which ORF34 serves as a hub for recruiting a viral transcription complex to ORF24 to promote late viral gene expression.
卡波氏肉瘤相关疱疹病毒（KSHV）是卡波氏肉瘤、原发性渗出性淋巴瘤和多中心卡斯特曼病的病原体。KSHV 在其宿主中建立了终身感染，并在潜伏和裂解感染状态之间交替。在裂解感染期间，裂解相关基因以时间方式表达，并分为即刻早期、早期和晚期基因转录本。ORF34 是一个早期-晚期基因，与几种病毒转录相关因子相互作用，但它的生理重要性仍知之甚少。在这里，我们通过使用细菌人工染色体系统生成 ORF34 缺失的 KSHV，研究了 ORF34 在 KSHV 感染过程中的作用。我们的结果表明，ORF34 缺失的 KSHV 晚期基因表达和病毒产生明显减弱，但不影响病毒 DNA 复制。ORF34 与转录因子 ORF18、ORF24、ORF31 和 ORF66 以及一个新的 ORF34 相互作用伙伴 ORF23 相互作用。ORF34 的 C 末端区域对于与 ORF24 的相互作用和病毒产生很重要。我们的数据支持这样一种模型，即 ORF34 作为一个枢纽，招募一个病毒转录复合物到 ORF24 以促进晚期病毒基因表达。
