Bao Chenyi, Chu Jun, Gao Qi, Yang Shasha, Gao Xiaoyu, Chen Wenwen, Yang Fuchun, Jiang Fei, Tong Chenxi, Lei Mingyi, Jiao Linlin, Li Jitong, Wei Kexin, Lian Xue, Li Kai, Tikoo Suresh Kumar, Osterrieder Nikolaus, Babiuk Lorne A, Li Yufeng, Jung Yong-Sam, Qian Yingjuan
The Sanya Institute of Nanjing Agricultural University, Laboratory of Emerging Animal Diseases and One Health, Nanjing Agricultural University, Nanjing, China.
MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
PLoS Pathog. 2025 Feb 3;21(2):e1012891. doi: 10.1371/journal.ppat.1012891. eCollection 2025 Feb.
Marek's disease virus (MDV), an alphaherpesvirus, causes severe immunosuppression and T cell lymphomas in chickens, known as Marek's disease (MD), an economically important poultry disease primarily controlled by vaccination. Importantly, it also serves as a comparative model for studying herpesvirus-induced tumor formation in humans. MDV encodes more than 100 genes, most of which have unknown functions. MDV LORF1 is unique to serotype I MDV (MDV-1), lacking homologs in other herpesviruses, and has not been explored yet. To this end, an infectious bacterial artificial chromosome (BAC) harboring the complete genome of the MDV-1 very virulent strain Md5 was generated, and the rescued rMd5 maintained biological properties similar to the parental virus both in vitro and in vivo. Subsequently, rMd5ΔLORF1, a recombinant Md5 virus deficient in pLORF1 expression, was generated by a frameshift mutation in the LORF1 gene. Chickens infected with rMd5ΔLORF1 exhibited a lower mortality rate and delayed bursal atrophy than those infected with the parental rMd5 and the revertant virus (rMd5-reLORF1). Consistently, viral loads of rMd5ΔLORF1 were obviously lower than those of rMd5 or rMd5-reLORF1 in the bursa, but not in the spleen. Importantly, we found that pLORF1 deficiency impairs viral replication in bursal B cells. Furthermore, we showed that pLORF1 associated with the cellular membrane, interacted with MDV structural proteins, and exhibited punctate colocalization with tegument or capsid proteins in the cytoplasm. Taken together, this study demonstrates for the first time that the MDV-1 unique gene LORF1 is involved in MDV-induced bursal atrophy but not in tumor formation.
马立克氏病病毒（MDV）是一种α疱疹病毒，可导致鸡严重免疫抑制和T细胞淋巴瘤，即马立克氏病（MD），这是一种主要通过疫苗接种控制的具有重要经济意义的家禽疾病。重要的是，它还作为研究人类疱疹病毒诱导肿瘤形成的比较模型。MDV编码100多个基因，其中大多数功能未知。MDV LORF1是I型MDV（MDV-1）所特有的，在其他疱疹病毒中缺乏同源物，尚未得到研究。为此，构建了一个携带MDV-1超强毒株Md5完整基因组的感染性细菌人工染色体（BAC），拯救的rMd5在体外和体内均保持与亲本病毒相似的生物学特性。随后，通过LORF1基因的移码突变产生了缺乏pLORF1表达的重组Md5病毒rMd5ΔLORF1。感染rMd5ΔLORF1的鸡比感染亲本rMd5和回复病毒（rMd5-reLORF1）的鸡死亡率更低，法氏囊萎缩延迟。一致地，rMd5ΔLORF1在法氏囊中的病毒载量明显低于rMd5或rMd5-reLORF1，但在脾脏中则不然。重要的是，我们发现pLORF1缺陷会损害病毒在法氏囊B细胞中的复制。此外，我们表明pLORF1与细胞膜相关，与MDV结构蛋白相互作用，并在细胞质中与被膜或衣壳蛋白表现出点状共定位。综上所述，本研究首次证明MDV-1独特基因LORF1参与MDV诱导的法氏囊萎缩，但不参与肿瘤形成。
