Crowell R C, Kiessling A A
Laboratory of Reproductive Biology, Department of Surgery, Harvard Medical School, 4 Blackfan Circle, Boston, MA 02115, USA.
Biochem Soc Trans. 2007 Jun;35(Pt 3):629-33. doi: 10.1042/BST0350629.
ERVs (endogenous retroviruses), which comprise 8-10% of mouse and human genomes, are present in thousands of copies, ranging in size from complete 9 kb virus to truncated partial sequences. Despite well-documented differential expression of ERVs in normal and diseased tissues, their biological significance remains controversial. Work in this laboratory revealed remarkably high ERV expression in mouse epididymis, but not in testis. Similar early studies revealed expression of human ERV-E4.1 in both testis and epididymis, but expression of other HERVs (human ERVs) was not examined. Using degenerate primers to conserved regions of reverse transcriptase specific for each of nine HERV families, we have detected expression of six HERV families in epididymis and three in testis. Differential HERV expression may reflect the fully differentiated state of epididymal epithelium in contrast with the immature germ cell population in the testis. These two tissues may therefore lay the groundwork not only for understanding the influence of cellular differentiation on HERV expression, but also to reveal HERVs that are routinely exposed to sperm.
内源性逆转录病毒（ERVs）占小鼠和人类基因组的8%-10%，以数千个拷贝形式存在，大小从完整的9 kb病毒到截短的部分序列不等。尽管有充分记录表明ERVs在正常组织和患病组织中的表达存在差异，但其生物学意义仍存在争议。本实验室的研究发现小鼠附睾中ERVs表达显著高，但睾丸中则不然。类似的早期研究发现人类ERV-E4.1在睾丸和附睾中均有表达，但未检测其他人类内源性逆转录病毒（HERVs）的表达。我们使用针对九个HERV家族各自逆转录酶保守区域的简并引物，在附睾中检测到六个HERV家族的表达，在睾丸中检测到三个HERV家族的表达。HERV表达的差异可能反映了附睾上皮细胞的完全分化状态，与睾丸中未成熟的生殖细胞群体形成对比。因此，这两种组织不仅可能为理解细胞分化对HERV表达的影响奠定基础，还可能揭示经常接触精子的HERVs。
