Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom.
PLoS One. 2012;7(7):e38983. doi: 10.1371/journal.pone.0038983. Epub 2012 Jul 3.
Although somatic homologous pairing is common in Drosophila it is not generally observed in mammalian cells. However, a number of regions have recently been shown to come into close proximity with their homologous allele, and it has been proposed that pairing might be involved in the establishment or maintenance of monoallelic expression. Here, we investigate the pairing properties of various imprinted and non-imprinted regions in mouse tissues and ES cells. We find by allele-specific 4C-Seq and DNA FISH that the Kcnq1 imprinted region displays frequent pairing but that this is not dependent on monoallelic expression. We demonstrate that pairing involves larger chromosomal regions and that the two chromosome territories come close together. Frequent pairing is not associated with imprinted status or DNA repair, but is influenced by chromosomal location and transcription. We propose that homologous pairing is not exclusive to specialised regions or specific functional events, and speculate that it provides the cell with the opportunity of trans-allelic effects on gene regulation.
虽然体细胞同源配对在果蝇中很常见，但在哺乳动物细胞中一般观察不到。然而，最近有许多区域被证明与它们的同源等位基因紧密接近，有人提出配对可能参与单等位基因表达的建立或维持。在这里，我们研究了小鼠组织和胚胎干细胞中各种印记和非印记区域的配对特性。我们通过等位基因特异性 4C-Seq 和 DNA FISH 发现，Kcnq1 印记区域显示出频繁的配对，但这并不依赖于单等位基因表达。我们证明配对涉及更大的染色体区域，并且两个染色体区域彼此紧密靠近。频繁的配对与印记状态或 DNA 修复无关，而是受染色体位置和转录的影响。我们提出，同源配对并非仅限于专门的区域或特定的功能事件，并且推测它为细胞提供了对基因调控的跨等位基因效应的机会。
