Human endogenous retroviruses (HERVs) are remnants of ancient retroviral germline infections. Most HERV sequences are silenced in somatic cells, but interest is emerging on the involvement of HERV derived transcripts and proteins in human physiology and disease. A HERV‐W encoded protein, syncytin‐1, has been co‐opted into fetal physiology, where it plays a role in trophoblast formation. Altered HERV transcription and expression of HERV derived proteins are associated with various cancer types and neurological diseases such as multiple sclerosis (MS). The implication of HERVs as potential mediators of both health and disease suggests important roles of regulatory mechanisms and alterations of these in physiological and pathological processes. The regulation of HERV sequences is mediated by a wide variety of mechanisms, and the focus of this review is on selected aspects of these, including epigenetic mechanisms such as CpG methylation and histone modifications of the HP1‐H3K9me axis, viral transactivation events, and regulatory perspectives of transient stimuli in the microenvironment. Increasing knowledge of the regulation of HERV sequences will not only contribute to the understanding of complex pathogeneses, but also may pinpoint potential targets for better diagnosis and treatment in complex diseases as MS.

中文翻译：

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人类内源性逆转录病毒表达的调节：胎儿发育中的元素以及在癌症和神经系统疾病发展中的可能作用

人内源性逆转录病毒（HERV）是古代逆转录病毒种系感染的残余物。多数HERV序列在体细胞中沉默，但人们对HERV衍生的转录物和蛋白质参与人体生理学和疾病的兴趣日益浓厚。HERV‐W编码的蛋白，syncytin-1，已被选入胎儿生理学，在滋养细胞形成中发挥作用。HERV转录和HERV衍生蛋白表达的改变与多种癌症类型和神经系统疾病（如多发性硬化症（MS））相关。HERV作为健康和疾病的潜在介质的暗示暗示了调节机制的重要作用及其在生理和病理过程中的改变。HERV序列的调节是由多种机制介导的，本综述的重点是这些方面的选定方面，包括表观遗传机制，例如CpG甲基化和HP1-H3K9me轴的组蛋白修饰，病毒反式激活事件以及微环境中瞬时刺激的调控观点。越来越多的关于HERV序列调控的知识将不仅有助于了解复杂的病原体，而且还可以为MS等复杂疾病的更好的诊断和治疗指明潜在的目标。