Nothias F, Fischer I, Murray M, Mirman S, Vincent J D
Institut Alfred Fessard, CNRS/UPR 2212, Gif-Sur-Yvettte, France.
J Comp Neurol. 1996 May 6;368(3):317-34. doi: 10.1002/(SICI)1096-9861(19960506)368:3<317::AID-CNE1>3.0.CO;2-8.
Microtubule-associated protein IB (MAP1B) is the first MAP to be detected in the developing nervous system, and it becomes markedly down-regulated postnatally. Its expression, particularly that of its phosphorylated isoform, is associated with axonal growth. To determine whether adult central nervous system (CNS) areas that retain immunoreactivity for MAP1B are associated with morphological plasticity, we compared the distribution of a phosphorylated MAP1B isoform (MAP1B-P) to the distribution of total MAP1B protein and MAP1B-mRNA. Although they were present only at very low levels, both protein and message were found ubiquitously in almost all adult CNS neurons. The intensity of staining, however, varied markedly among different regions, with only a few nuclei retaining relatively high levels. MAP1B-P was restricted to axons, whereas total MAP1B was present in cell bodies and processes. Relatively to total MAP1B protein and its mRNA, MAP1B-P levels decreased more dramatically with maturation, and they were detectable in only a few specific areas that underwent structural modifications. These included primary afferents and motor neurons, olfactory tubercles, habenular and raphe projections to interpeduncular nuclei, septum, and the hypothalamus. The distribution pattern of MAP1B-P was compared to that of the embryonic N-CAM rich in polysialic acid (PSA-NCAM). We found that the PSA-NCAM immunostaining was largely overlapped with that of MAP1B-P in the adult CNS. These results suggest that, like PSA-NCAM, MAP1B may be one of the molecules expressed during brain development that also plays a role in structural remodeling in the adult.
微管相关蛋白IB（MAP1B）是在发育中的神经系统中最早被检测到的微管相关蛋白，出生后其表达会显著下调。它的表达，尤其是其磷酸化异构体的表达，与轴突生长相关。为了确定对MAP1B保持免疫反应性的成体中枢神经系统（CNS）区域是否与形态可塑性相关，我们比较了磷酸化MAP1B异构体（MAP1B-P）的分布与总MAP1B蛋白和MAP1B-mRNA的分布。尽管它们仅以非常低的水平存在，但在几乎所有成体CNS神经元中都普遍发现了蛋白质和信息。然而，不同区域的染色强度差异显著，只有少数细胞核保持相对较高的水平。MAP1B-P局限于轴突，而总MAP1B存在于细胞体和突起中。相对于总MAP1B蛋白及其mRNA，MAP1B-P水平随着成熟而下降得更为显著，并且仅在少数经历结构修饰的特定区域中可检测到。这些区域包括初级传入纤维和运动神经元、嗅结节、缰核和中缝向脚间核、隔区和下丘脑的投射。将MAP1B-P的分布模式与富含多唾液酸的胚胎N-CAM（PSA-NCAM）的分布模式进行了比较。我们发现，在成体CNS中，PSA-NCAM免疫染色与MAP1B-P的免疫染色在很大程度上重叠。这些结果表明，与PSA-NCAM一样，MAP1B可能是在脑发育过程中表达的分子之一，并且在成体中也参与结构重塑。
