Generation and Characterization of Knock-in Mouse Models Expressing Versions of Huntingtin with Either an N17 or a Combined PolyQ and Proline-Rich Region Deletion.
Generation and Characterization of Knock-in Mouse Models Expressing Versions of Huntingtin with Either an N17 or a Combined PolyQ and Proline-Rich Region Deletion.
复制标题
DOI：
10.3233/jhd-160231
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Zeitlin SO
中科院分区：
文献类型：
--
作者：
André EA;Braatz EM;Liu JP;Zeitlin SO
背景：哺乳动物亨廷顿蛋白（HTT）的聚谷氨酰胺（polyQ）片段两侧有一个高度保守的17个氨基酸n端结构域（N17）和一个富含脯氨酸的区域（PRR）。PRR是许多HTT相互作用蛋白的结合位点，N17结构域调节几种正常的HTT功能，包括HTT与膜和细胞器结合的能力。目的：探讨删除小鼠亨廷顿蛋白（Htt） N17结构域或其polyQ延伸与PRR （QP）结合对小鼠正常Htt功能的影响。方法：生成表达缺乏N17结构域（HttΔN17）或polyQ和PRR结构域（HttΔQP）的Htt敲入小鼠，并对其行为、自噬功能和神经病理学进行评估。结果：纯合子和半合子HttΔQP/ΔQP、HttΔN17/ΔN17、HttΔQP/ -和HttΔN17/ -小鼠在预期的孟德尔频率下产生。与对照组相比，HttΔQP/ΔQP突变体在运动协调方面表现出改善（Htt+/+）。相比之下，HttΔN17/ΔN17突变体在运动协调方面没有表现出任何变化，但他们在空间学习方面确实表现出不同的变化，这取决于他们在测试时的年龄。与对照组相比，这两种突变体在基底自噬方面都没有表现出任何变化，但与对照组相比，24月龄HttΔN17/ΔN17小鼠的背纹状体丘脑纹状体突触减少。结论：这些发现支持了Htt的N17和QP结构域在早期胚胎发育中是必不可少的，但在中枢神经系统的发育或维持中可能对Htt的功能更重要。
Background: The polyglutamine (polyQ) stretch of the Huntingtin protein (HTT) in mammals is flanked by a highly conserved 17 amino acid N-terminal domain (N17), and a proline-rich region (PRR). The PRR is a binding site for many HTT-interacting proteins, and the N17 domain regulates several normal HTT functions, including HTT’s ability to associate with membranes and organelles. Objective: This study investigates the consequence of deleting mouse Huntingtin’s (Htt’s) N17 domain or a combination of its polyQ stretch and PRR (QP) on normal Htt function in mice. Methods: Knock-in mice expressing versions of Htt lacking either the N17 domain (HttΔN17) or both the polyQ and PRR domains (HttΔQP) were generated, and their behavior, autophagy function, and neuropathology were evaluated. Results: Homozygous and hemizygous HttΔQP/ΔQP, HttΔN17/ΔN17, HttΔQP/–, and HttΔN17/– mice were generated at the expected Mendelian frequency. HttΔQP/ΔQP mutants exhibit improvements in motor coordination compared to controls (Htt+/+). In contrast, HttΔN17/ΔN17 mutants do not exhibit any changes in motor coordination, but they do display variable changes in spatial learning that are dependent on their age at testing. Neither mutant exhibited any changes in basal autophagy in comparison to controls, but thalamostriatal synapses in the dorsal striatum of 24-month-old HttΔN17/ΔN17 mice were decreased compared to controls. Conclusions: These findings support the hypothesis that Htt’s N17 and QP domains are dispensable for its critical functions during early embryonic development, but are likely more important for Htt functions in CNS development or maintenance.