Andoh Kiyohiko, Nishimori Asami, Matsuura Yuichi
National Institute of Animal Health, National Agriculture and Food Research Organization , Tsukuba, Ibaraki, Japan.
Microbiol Spectr. 2023 Sep 6;11(5):e0085523. doi: 10.1128/spectrum.00855-23.
Viruses utilize several strategies to cause latent infection and evade host immune responses. Long non-coding RNA (lncRNA), a class of non-protein-encoding RNA that regulates various cellular functions by interacting with RNA-binding proteins, plays important roles for viral latency in several viruses, such as herpesviruses and retroviruses, due to its lack of antigenicity. Bovine leukemia virus (BLV), which belongs to the family Retroviridae, encodes the BLV-derived lncRNA AS1-S, which is a major transcript expressed in latently infected cells. We herein identified bovine heterogeneous nuclear ribonucleoprotein M (hnRNPM), an RNA-binding protein located in the nucleus, as the binding partner of AS1-S using an RNA-protein pull-down assay. The pull-down assay using recombinant hnRNPM mutants showed that RNA recognition motifs (RRMs) 1 and 2, located in the N-terminal region of bovine hnRNPM, were responsible for the binding to AS1-S. Furthermore, RNA immunoprecipitation (RIP) assay results showed that the expression of AS1-S increased the number of mRNAs that co-immunoprecipitated with bovine hnRNPM in MDBK cells. These results suggested that AS1-S could alter the interaction between hnRNPM and host mRNAs, potentially interfering with cellular functions during the initial phase of mRNA maturation in the nucleus. Since most of the identified mRNAs that exhibited increased binding to hnRNPM were correlated with the KEGG term "Pathways in cancer," AS1-S might affect the proliferation and expansion of BLV-infected cells and contribute to tumor progression. IMPORTANCE BLV infects bovine B cells and causes malignant lymphoma, a disease that greatly affects the livestock industry. Due to its low incidence and long latent period, the molecular mechanisms underlying the progression of lymphoma remain enigmatic. Several non-coding RNAs (ncRNAs), such as miRNA and lncRNA, have recently been discovered in the BLV genome, and the relationship between BLV pathogenesis and these ncRNAs is attracting attention. However, most of the molecular functions of these transcripts remain unidentified. To the best of our knowledge, this is the first report describing a molecular function for the BLV-derived lncRNA AS1-S. The findings reported herein reveal a novel mechanism underlying BLV pathogenesis that could provide important insights for not only BLV research but also comparative studies of retroviruses.
病毒利用多种策略引发潜伏感染并逃避宿主免疫反应。长链非编码RNA（lncRNA）是一类通过与RNA结合蛋白相互作用来调节多种细胞功能的非蛋白质编码RNA，由于其缺乏抗原性，在几种病毒（如疱疹病毒和逆转录病毒）的病毒潜伏过程中发挥重要作用。牛白血病病毒（BLV）属于逆转录病毒科，编码BLV衍生的lncRNA AS1-S，它是潜伏感染细胞中表达的主要转录本。我们在此使用RNA-蛋白质下拉实验鉴定了位于细胞核中的RNA结合蛋白牛异质性核核糖核蛋白M（hnRNPM）作为AS1-S的结合伴侣。使用重组hnRNPM突变体进行的下拉实验表明，位于牛hnRNPM N端区域的RNA识别基序（RRMs）1和2负责与AS1-S的结合。此外，RNA免疫沉淀（RIP）实验结果表明，AS1-S的表达增加了MDBK细胞中与牛hnRNPM共免疫沉淀的mRNA数量。这些结果表明，AS1-S可能会改变hnRNPM与宿主mRNA之间的相互作用，可能在细胞核中mRNA成熟的初始阶段干扰细胞功能。由于大多数鉴定出的与hnRNPM结合增加的mRNA与KEGG术语“癌症通路”相关，AS1-S可能会影响BLV感染细胞的增殖和扩张，并促进肿瘤进展。重要性：BLV感染牛B细胞并导致恶性淋巴瘤，这是一种对畜牧业有重大影响的疾病。由于其发病率低且潜伏期长，淋巴瘤进展的分子机制仍然不明。最近在BLV基因组中发现了几种非编码RNA（ncRNA），如miRNA和lncRNA，BLV发病机制与这些ncRNA之间的关系正受到关注。然而，这些转录本的大多数分子功能仍未确定。据我们所知，这是第一份描述BLV衍生的lncRNA AS1-S分子功能的报告。本文报道的研究结果揭示了BLV发病机制的一种新机制，这不仅可为BLV研究提供重要见解，也可为逆转录病毒的比较研究提供重要见解。
