The Roslin Institute, RDSVS, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, UK.
Leiden University Medical Center, Leiden University, Leiden, The Netherlands.
Transgenic Res. 2024 Aug;33(4):255-266. doi: 10.1007/s11248-024-00395-9. Epub 2024 Jul 9.
The p75NTR neurotrophin receptor has positive and negative roles regulating cell survival in the nervous system. Unambiguous interpretation of p75NTR function in vivo has been complicated, however, by residual expression of alternate forms of p75NTR protein in initial p75NTR knock-out mouse models. As rats are the preferred rodent for studying brain and behaviour, and to simplify interpretation of the knock-out phenotype, we report here the generation of a mutant rat devoid of the p75NTR protein. TALEN-mediated recombination in embryonic stem cells (ESCs) was used to flank exon 2 of p75NTR with Lox P sites and produce transgenic rats carrying either un-recombined floxed p75NTR, or recombined, exon-2 deleted p75NTR alleles. Crossing p75NTR rats with a Cre-deleter strain efficiently removed exon 2 in vivo. Excision of exon 2 causes a frameshift after p75NTR Gly23 and eliminated p75NTR protein expression. Rats lacking p75NTR were healthy, fertile, and histological analysis did not reveal significant changes in cellular density or overall structure in their brains. p75NTR function is therefore largely dispensable for normal development, growth and basal homeostasis in the rat. However, the availability of constitutive and conditional p75NTR rats provides new opportunities to investigate specific roles of p75NTR upon injury and during tissue repair.
p75NTR 神经营养因子受体在调节神经系统中的细胞存活方面具有正反两方面的作用。然而，由于在最初的 p75NTR 敲除小鼠模型中仍存在 p75NTR 蛋白的其他形式表达，因此 p75NTR 功能的明确解释变得复杂。由于大鼠是研究大脑和行为的首选啮齿动物，并且为了简化敲除表型的解释，我们在此报告了一种缺乏 p75NTR 蛋白的突变大鼠的产生。TALEN 介导的胚胎干细胞 (ESC) 重组用于将 p75NTR 的外显子 2 侧翼用 Lox P 位点包围，并产生携带未重组 floxed p75NTR 或重组、外显子 2 缺失的 p75NTR 等位基因的转基因大鼠。将 p75NTR 大鼠与 Cre 缺失株杂交可有效地在体内切除外显子 2。外显子 2 的缺失导致 p75NTR Gly23 后的移码，并消除了 p75NTR 蛋白的表达。缺乏 p75NTR 的大鼠健康、有生育能力，组织学分析并未显示其大脑中的细胞密度或整体结构有明显变化。因此，p75NTR 功能在大鼠的正常发育、生长和基础稳态中很大程度上是可有可无的。然而，组成型和条件性 p75NTR 大鼠的可用性为研究 p75NTR 在损伤和组织修复过程中的特定作用提供了新的机会。
