Emergence of three myelin proteins in oligodendrocytes cultured without neurons.
Emergence of three myelin proteins in oligodendrocytes cultured without neurons.
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DOI：
10.1083/jcb.102.2.384
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发表时间：
1986-02
期刊：
影响因子：
--
通讯作者：
Lazzarini RA
中科院分区：
文献类型：
--
作者：
Dubois-Dalcq M;Behar T;Hudson L;Lazzarini RA
从新生大鼠脑和视神经中分离培养髓鞘形成细胞--少突胶质细胞，以分析髓鞘相关糖蛋白(MAG)和蛋白脂蛋白(PLP)这两种跨膜髓鞘蛋白在低血清和无神经元条件下是否与髓鞘碱性蛋白(MBP)一起表达。使用双标记免疫荧光技术，我们研究了这三种髓鞘蛋白在表达半乳糖脑苷脂(GC)的细胞中何时何地出现，GC是少突胶质细胞膜的特异性标志。我们发现，从脑和视神经来源的一部分少突胶质细胞在GC出现约一周后表达MBP、MAG和PLP，这发生在出生前后。在脑源性少突胶质细胞中，MBP和MAG在出生后第5~7天首先出现，1~2天后出现PLP。当时，这三种蛋白质都局限在细胞体内，尽管GC阳性过程的广泛网络已经发展起来。每种蛋白都有一个特定的细胞质定位：弥漫性的MBP，MAG的大部分核周，PLP的颗粒状。有趣的是，MAG可能参与了神经胶质-轴突的相互作用，是出生后大约10天在这些过程中检测到的第一个髓鞘蛋白。MBP和PLP仅见于15d后，所有GC阳性细胞均在第19天表达这三种髓鞘蛋白。同时，在少突胶质细胞表面聚集了大量的膜和髓鞘螺旋体。这三种髓鞘蛋白在体外的顺序出现、胞浆位置和表达高峰遵循与体内描述的相似的模式，因此，与持续的神经元影响无关。这样的培养为研究调节髓鞘蛋白表达的因素提供了一个方便的系统。
Oligodendrocytes, the myelin-forming cells of the central nervous system, were cultured from newborn rat brain and optic nerve to allow us to analyze whether two transmembranous myelin proteins, myelin- associated glycoprotein (MAG) and proteolipid protein (PLP), were expressed together with myelin basic protein (MBP) in defined medium with low serum and in the absence of neurons. Using double label immunofluorescence, we investigated when and where these three myelin proteins appeared in cells expressing galactocerebroside (GC), a specific marker for the oligodendrocyte membrane. We found that a proportion of oligodendrocytes derived from brain and optic nerve invariably express MBP, MAG, and PLP about a week after the emergence of GC, which occurs around birth. In brain-derived oligodendrocytes, MBP and MAG first emerge between the fifth and the seventh day after birth, followed by PLP 1 to 2 d later. All three proteins were confined to the cell body at that time, although an extensive network of GC positive processes had already developed. Each protein shows a specific cytoplasmic localization: diffuse for MBP, mostly perinuclear for MAG, and particulate for PLP. Interestingly, MAG, which may be involved in glial-axon interactions, is the first myelin protein detected in the processes at approximately 10 d after birth. MBP and PLP are only seen in these locations after 15 d. All GC-positive cells express the three myelin proteins by day 19. Simultaneously, numerous membrane and myelin whorls accumulate along the oligodendrocyte surface. The sequential emergence, cytoplasmic location, and peak of expression of these three myelin proteins in vitro follow a pattern similar to that described in vivo and, therefore, are independent of continuous neuronal influences. Such cultures provide a convenient system to study factors regulating expression of myelin proteins.