Ferhat L, Represa A, Ferhat W, Ben-Ari Y, Khrestchatisky M
Université René Descartes, Paris V, INSERM U-29, Paris, France.
Eur J Neurosci. 1998 Jan;10(1):161-71. doi: 10.1046/j.1460-9568.1998.00044.x.
The brain microtubule-associated protein MAP2 family is composed of high-molecular-weight (MAP2a and MAP2b) and low-molecular-weight (MAP2c and MAP2d) isoforms. The common C-terminal region of HMW MAP2 and MAP2c contains three repeated microtubule-binding domains while MAP2d comprises four repeats. MAP2c mRNA is known to be expressed at high levels in the immature brain. We show that in the brains of rat pups, MAP2c mRNAs are indeed expressed at high levels compared with MAP2d. However, in adult rat brains, MAP2d mRNA levels are higher than MAP2c. In order to identify the neural cells expressing MAP2d, we used in situ hybridization. In vivo, we show that MAP2d mRNA is expressed in well-identified neuronal populations of the brain. In primary cultures of hippocampal neurones, double-labelling experiments confirm that MAP2d is clearly expressed in neurones. We also evaluated in this study the subcellular distribution of the MAP2d mRNAs in cultured hippocampal neurones and we report that in contrast with MAP2b mRNAs, mostly localized in dendrites, MAP2d mRNAs are essentially located in neuronal cell bodies.
脑微管相关蛋白MAP2家族由高分子量（MAP2a和MAP2b）和低分子量（MAP2c和MAP2d）亚型组成。高分子量MAP2和MAP2c的共同C末端区域包含三个重复的微管结合结构域，而MAP2d包含四个重复。已知MAP2c mRNA在未成熟大脑中高水平表达。我们发现，在幼鼠大脑中，与MAP2d相比，MAP2c mRNA确实高水平表达。然而，在成年大鼠大脑中，MAP2d mRNA水平高于MAP2c。为了鉴定表达MAP2d的神经细胞，我们使用了原位杂交。在体内，我们发现MAP2d mRNA在大脑中明确鉴定的神经元群体中表达。在海马神经元的原代培养中，双标记实验证实MAP2d在神经元中清晰表达。我们在本研究中还评估了培养的海马神经元中MAP2d mRNA的亚细胞分布，我们报告，与主要定位于树突的MAP2b mRNA相反，MAP2d mRNA主要位于神经元细胞体中。
