Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK.
Development. 2011 Oct;138(20):4443-50. doi: 10.1242/dev.071001. Epub 2011 Aug 31.
The majority of axons in the central nervous system (CNS) are eventually myelinated by oligodendrocytes, but whether the timing and extent of myelination in vivo reflect intrinsic properties of oligodendrocytes, or are regulated by axons, remains undetermined. Here, we use zebrafish to study CNS myelination at single-cell resolution in vivo. We show that the large caliber Mauthner axon is the first to be myelinated (shortly before axons of smaller caliber) and that the presence of supernumerary large caliber Mauthner axons can profoundly affect myelination by single oligodendrocytes. Oligodendrocytes that typically myelinate just one Mauthner axon in wild type can myelinate multiple supernumerary Mauthner axons. Furthermore, oligodendrocytes that exclusively myelinate numerous smaller caliber axons in wild type can readily myelinate small caliber axons in addition to the much larger caliber supernumerary Mauthner axons. These data indicate that single oligodendrocytes can myelinate diverse axons and that their myelinating potential is actively regulated by individual axons.
中枢神经系统（CNS）中的大多数轴突最终由少突胶质细胞髓鞘化，但髓鞘化的时间和程度是反映少突胶质细胞的内在特性，还是受轴突调节，仍未确定。在这里，我们使用斑马鱼在体内以单细胞分辨率研究 CNS 髓鞘化。我们表明，大口径的 Mauthner 轴突是第一个被髓鞘化的（在小口径轴突之前不久），并且多余的大口径 Mauthner 轴突的存在可以深刻影响单个少突胶质细胞的髓鞘化。在野生型中，通常只髓鞘化一个 Mauthner 轴突的少突胶质细胞可以髓鞘化多个多余的 Mauthner 轴突。此外，在野生型中专门髓鞘化许多小口径轴突的少突胶质细胞可以很容易地除了更大口径的多余 Mauthner 轴突之外，还可以髓鞘化小口径轴突。这些数据表明，单个少突胶质细胞可以髓鞘化不同的轴突，并且它们的髓鞘化潜力受到单个轴突的主动调节。
