Department of Surgery, University of California, Davis, Sacramento, CA, USA.
Retrovirology. 2011 Oct 12;8:82. doi: 10.1186/1742-4690-8-82.
Endogenous retroviruses (ERVs), including murine leukemia virus (MuLV) type-ERVs (MuLV-ERVs), are presumed to occupy ~10% of the mouse genome. In this study, following the identification of a full-length MuLV-ERV by in silico survey of the C57BL/6J mouse genome, its distribution in different mouse strains and expression characteristics were investigated.
Application of a set of ERV mining protocols identified a MuLV-ERV locus with full coding potential on chromosome 8 (named ERVmch8). It appears that ERVmch8 shares the same genomic locus with a replication-incompetent MuLV-ERV, called Emv2; however, it was not confirmed due to a lack of relevant annotation and Emv2 sequence information. The ERVmch8 sequence was more prevalent in laboratory strains compared to wild-derived strains. Among 16 different tissues of ~12 week-old female C57BL/6J mice, brain homogenate was the only tissue with evident expression of ERVmch8. Further ERVmch8 expression analysis in six different brain compartments and four peripheral neuronal tissues of C57BL/6J mice revealed no significant expression except for the cerebellum in which the ERVmch8 locus' low methylation status was unique compared to the other brain compartments. The ERVmch8 locus was found to be surrounded by genes associated with neuronal development and/or inflammation. Interestingly, cerebellum-specific ERVmch8 expression was age-dependent with almost no expression at 2 weeks and a plateau at 6 weeks.
The ecotropic ERVmch8 locus on the C57BL/6J mouse genome was relatively undermethylated in the cerebellum, and its expression was cerebellum-specific and age-dependent.
内源性逆转录病毒（ERVs），包括鼠白血病病毒（MuLV）型 ERVs（MuLV-ERVs），据推测占据了约 10%的小鼠基因组。在这项研究中，通过对 C57BL/6J 小鼠基因组的计算机分析，发现了一个全长 MuLV-ERV 后，我们调查了其在不同小鼠品系中的分布和表达特征。
应用一组 ERV 挖掘方案，在 8 号染色体上鉴定出一个具有完整编码潜力的 MuLV-ERV 基因座（命名为 ERVmch8）。看起来 ERVmch8 与一个复制失活的 MuLV-ERV，Emv2，共享相同的基因组位置；然而，由于缺乏相关注释和 Emv2 序列信息，这一点尚未得到证实。在实验室品系中，ERVmch8 序列比野生来源的品系更为普遍。在 12 周龄雌性 C57BL/6J 小鼠的 16 种不同组织中，脑组织匀浆是唯一表现出 ERVmch8 明显表达的组织。进一步在 C57BL/6J 小鼠的六个不同脑区和四个周围神经元组织中进行 ERVmch8 表达分析，除了小脑外，其他组织均无明显表达，而小脑中 ERVmch8 基因座的低甲基化状态与其他脑区不同。发现 ERVmch8 基因座被与神经元发育和/或炎症相关的基因所包围。有趣的是，小脑特异性 ERVmch8 表达与年龄有关，在 2 周龄时几乎没有表达，在 6 周龄时达到平台期。
C57BL/6J 小鼠基因组上的嗜性 ERVmch8 基因座在小脑区相对低甲基化，其表达具有小脑特异性和年龄依赖性。
