Nakajima K, Ikenaka K, Kagawa T, Aruga J, Nakao J, Nakahira K, Shiota C, Kim S U, Mikoshiba K
Division of Regulation of Macromolecular Function, Osaka University, Japan.
J Neurochem. 1993 Apr;60(4):1554-63. doi: 10.1111/j.1471-4159.1993.tb03321.x.
Myelin basic protein (MBP), a major protein of myelin, is thought to play an important role in myelination, which occurs postnatally in mouse. Here we report that the MBP gene is expressed from the 12th embryonic day in mouse brain and that most of the predominant embryonic isoforms are not those reported previously. These isoforms have a deletion of a sequence encoded by exon 5 from the well-known isoforms. These isoforms show a unique developmental profile, i.e., they peak in the embryonic stage and decrease thereafter. In jimpy, a dysmyelinating mutant, the level of these isoforms remains high even in the older ages. These results suggest that MBPs have heretofore unknown functions unrelated to myelination before myelinogenesis begins. The possible presence of 18 isoforms of MBP mRNA, which are classified into at least three groups with different developmental profiles, is also reported here.
髓鞘碱性蛋白（MBP）是髓鞘的一种主要蛋白质，被认为在髓鞘形成过程中发挥重要作用，髓鞘形成在小鼠出生后发生。在此我们报告，MBP基因在小鼠脑胚胎第12天开始表达，并且大多数主要的胚胎异构体并非先前报道的那些。这些异构体相对于知名异构体缺失了外显子5编码的序列。这些异构体呈现出独特的发育模式，即它们在胚胎阶段达到峰值，随后下降。在jimpy（一种脱髓鞘突变体）中，即使在较年长时这些异构体的水平仍保持较高。这些结果表明，在髓鞘形成开始之前，MBP具有迄今未知的与髓鞘形成无关的功能。本文还报道了可能存在18种MBP mRNA异构体，它们至少被分为具有不同发育模式的三组。
