Objective: To explore the regulatory effect of fragile X mental retardation protein (FMRP) on the translation of microtubule associated protein 1B (MAP1B).
Methods: The expressions of MAP1B protein and MAP1B mRNA in the brains of 1-week and 6-week old fragile X mental retardation-1 (Fmr1) knockout (KO) mice were investigated by immunohistochemistry, Western blot, and in situ hybridization, with the age-matched wild type mice (WT) as controls.
Results: The mean optical density (MOD) of MAP1B was significantly decreased in each brain region in KO6W compared with WT6W, whereas in KO1W, this decrease was only found in the hippocampus and cerebellum. MAP1B in 6-week mice was much less than that in 1-week mice of the same genotype. The results of Western blot and in situ hybridization showed that MAP1B protein and MAP1B mRNA were significantly decreased in the hippocampus of both KO1W and KO6W.
Conclusion: The decreased MAP1B protein and MAP1B mRNA in the Fmr1 knockout mice indicate that FMRP may positively regulate the expression of MAP1B.
目的: 探讨脆性X智能低下蛋白(fragile X mental retardation protein, FMRP)对微맜相关蛋白1B(microtubule associated protein 1B, MAP1B) 是否具有调控作用。
方法: 应用免疫组化、 免疫印记和原位杂交的方法, 对 1 周龄和 6 周龄的 Fmr1 基因敲除型 (KO) 和同龄野生型 (WT) 小鼠脑组织 MAP1B 及 MAP1B mRNA 进行分析。
结果: 免疫组化的结果显示: 6 周龄 KO 小鼠各个脑区 MAP1B 的平均光密度值 (MOD) 值均显著低于同龄 WT 小鼠 (P < 0.05), 1 周龄 KO 小鼠仅在小脑和海马显著降低 (P < 0.01); 各脑区 MAP1B 的 MOD 值在 6 周龄小鼠均比同基因型的 1 周龄小鼠显著降低(P < 0.05)。 免疫印记和原位杂交结果分别显示 MAP1B 及 MAP1B mRNA 在 KO 小鼠的海马组织均显著降低(P < 0.05)。
结论: MAP1B和 MAP1B mRNA在 Fmr1 基因敲除小鼠脑组织的表达均显著减少, 提示 FMRP 可能正性调节 MAP1B 的表达。