Many pathogens, including Kaposi’s sarcoma herpesvirus (KSHV), lack tractable small animal models. KSHV persists as a multi-copy, nuclear episome in latently infected cells. KSHV latency-associated nuclear antigen (kLANA) binds viral terminal repeat (kTR) DNA to mediate episome persistence. Model pathogen murine gammaherpesvirus 68 (MHV68) mLANA acts analogously on mTR DNA. kLANA and mLANA differ substantially in size and kTR and mTR show little sequence conservation. Here, we find kLANA and mLANA act reciprocally to mediate episome persistence of TR DNA. Further, kLANA rescued mLANA deficient MHV68, enabling a chimeric virus to establish latent infection in vivo in germinal center B cells. The level of chimeric virus in vivo latency was moderately reduced compared to WT infection, but WT or chimeric MHV68 infected cells had similar viral genome copy numbers as assessed by immunofluorescence of LANA intranuclear dots or qPCR. Thus, despite more than 60 Ma of evolutionary divergence, mLANA and kLANA act reciprocally on TR DNA, and kLANA functionally substitutes for mLANA, allowing kLANA investigation in vivo. Analogous chimeras may allow in vivo investigation of genes of other human pathogens.

许多病原体，包括卡波济氏肉瘤疱疹病毒（KSHV），缺乏易处理的小动物模型。KSHV在潜伏感染的细胞中以多拷贝核附加体的形式持续存在。KSHV潜伏期相关的核抗原（kLANA）结合病毒末端重复（kTR）DNA来介导附加体持久性。模型病原体鼠丙种疱疹病毒68（MHV68）mLANA类似地作用于mTR DNA。kLANA和mLANA的大小基本不同，kTR和mTR几乎没有序列保守性。在这里，我们发现kLANA和mLANA相互起作用，以介导TR DNA的附加体持久性。此外，kLANA挽救了缺乏mLANA的MHV68，使嵌合病毒能够在生发中心B细胞中在体内建立潜在感染。与WT感染相比，嵌合病毒的体内潜伏期水平有所降低，但是野生型或嵌合MHV68感染的细胞具有相似的病毒基因组拷贝数，这是通过LANA核内斑点或qPCR的免疫荧光评估得出的。因此，尽管进化差异超过60 Ma，mLANA和kLANA仍然对TR DNA起作用，并且kLANA在功能上替代了mLANA，从而可以进行体内kLANA研究。类似的嵌合体可以允许体内研究其他人类病原体的基因。