Role of the Short Telomeric Repeat Region in Marek's Disease Virus Replication, Genomic Integration, and Lymphomagenesis
Role of the Short Telomeric Repeat Region in Marek's Disease Virus Replication, Genomic Integration, and Lymphomagenesis
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DOI：
10.1128/jvi.02437-14
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发表时间：
2014-12-01
影响因子：
5.4
通讯作者：
Kaufer, Benedikt B.
中科院分区：
文献类型：
--
作者：
Greco, Annachiara;Fester, Nadine;Kaufer, Benedikt B.
马立克氏病病毒（MDV）是一种细胞相关的α疱疹病毒，可引起鸡的全身性多神经炎和T细胞淋巴瘤。MDV能够将其基因组整合到宿主端粒中，但对其整合机制知之甚少。MDV基因组在其线性基因组的末端具有两个端粒重复序列（TMR）阵列：多端粒重复序列（mTMR），具有高达100个重复序列的可变数目，和短端粒重复序列（sTMR），具有固定数目的6个重复序列。mTMR最近被证明在MDV整合和肿瘤形成中起重要作用;然而，sTMR的功能仍然未知。在这项研究中，我们证明，在MDV基因组中的sTMR的删除废除病毒复制，而广泛的突变的sTMR不，表明存在的sTMR，但不是sTMR序列本身是重要的。此外，我们产生了一组截短突变体来确定sTMR的最小长度，并观察到sTMR长度和MDV复制之间的直接相关性。为了解决sTMR在MDV复制、整合和肿瘤发生中的作用，将sTMR序列替换为乱序重复序列（vsTMR_mut）。vsTMR_mut在体外复制亲本病毒和回复突变体病毒。然而，在体内，在感染vsTMR_mut的鸡中观察到疾病和肿瘤发生率的显著降低，这也与肿瘤细胞中病毒整合位点数量的减少相关。综上所述，我们的数据表明，sTMR在MDV基因组复制，发病机制和MDV诱导的肿瘤形成中起着核心作用。重要的是，马立克氏病病毒（MDV）是一种高度致瘤的α疱疹病毒，感染鸡，并造成很高的经济损失，在家禽业。MDV将其遗传物质整合到宿主端粒中，这是一个对有效形成肿瘤至关重要的过程。MDV基因组在其线性基因组的末端具有两个端粒重复序列（TMR）阵列，其与宿主端粒相同并且被称为mTMR和sTMR。mTMR最近已被证明参与MDV整合，而sTMR的功能仍然未知。在这里，我们证明了sTMR序列的存在和长度，而不是确切的核苷酸序列，是至关重要的MDV复制。此外，sTMR有助于MDV的高整合频率，并且对于MDV的致病性和肿瘤形成是重要的。由于许多疱疹病毒携带端粒重复序列（TMR）阵列，MDV可作为确定疱疹病毒TMR在复制、整合和发病机制中作用的模型。
Marek's disease virus (MDV) is a cell-associated alphaherpesvirus that causes generalized polyneuritis and T-cell lymphomas in chickens. MDV is able to integrate its genome into host telomeres, but the mechanism of integration is poorly understood. The MDV genome harbors two arrays of telomeric repeats (TMR) at the ends of its linear genome: multiple telomeric repeats (mTMR), with a variable number of up to 100 repeats, and short telomeric repeats (sTMR), with a fixed number of 6 repeats. The mTMR have recently been shown to play an important role in MDV integration and tumor formation; however, the functions of the sTMR have remained unknown. In this study, we demonstrate that deletion of the sTMR in the MDV genome abrogates virus replication, while extensive mutation of the sTMR does not, indicating that the presence of the sTMR but not the sTMR sequence itself is important. Furthermore, we generated a panel of truncation mutants to determine the minimal length of the sTMR and observed a direct correlation between sTMR length and MDV replication. To address the role of sTMR in MDV replication, integration, and tumorigenesis, sTMR sequences were replaced by a scrambled repeated sequence (vsTMR_mut). vsTMR_mut replicated comparably to parental and revertant viruses in vitro. In vivo, however, a significant reduction in disease and tumor incidence was observed in chickens infected with vsTMR_mut that also correlated with a reduced number of viral integration sites in tumor cells. Taken together, our data demonstrate that the sTMR play a central role in MDV genome replication, pathogenesis, and MDV-induced tumor formation.IMPORTANCEMarek's disease virus (MDV) is a highly oncogenic alphaherpesvirus that infects chickens and causes high economic losses in the poultry industry. MDV integrates its genetic material into host telomeres, a process that is crucial for efficient tumor formation. The MDV genome harbors two arrays of telomeric repeats (TMR) at the ends of its linear genome that are identical to host telomeres and that are termed mTMR and sTMR. mTMR have been recently shown to be involved in MDV integration, while the functions of sTMR remain unknown. Here, we demonstrate that the presence and length of sTMR sequence, but not the exact nucleotide sequence, are crucial for MDV replication. Furthermore, the sTMR contribute to the high integration frequency of MDV and are important for MDV pathogenesis and tumor formation. As a number of herpesviruses harbor arrays of telomeric repeats (TMR), MDV serves as a model to determine the role of the herpesvirus TMR in replication, integration, and pathogenesis.