Hr基因敲除小鼠模型的构建和表型分析

Construction of a Hr mutant knockout mouse model and phenotypic analysis

目的建立基因敲除小鼠以深入研究无毛基因(hairless,Hr)的功能。方法利用类转录激活因子效应因子核酸酶(transcription activator-like effector nucleases,TALENs)技术,制备Hr基因敲除小鼠,观察基因敲除小鼠毛发生长发育规律,并取部分皮肤组织石蜡切片,显微镜下分析结果。结果获得一个在Hr基因编码区86~87位有2个碱基缺失的首建鼠,产生了TGA终止密码子。通过与野生型鼠杂交获得阳性子代,进行同窝交配,传至第2代小鼠14 d开始脱发,30 d左右毛发脱净,并终身保持无毛。皮肤组织学观察发现真皮内形成大小不等的包囊。研究结果表明成功建立的Hr基因敲除小鼠表现出毛发生长异常。结论证明了无毛基因与毛发生长发育的密切关系,为研究Hr基因的精确功能提供了良好的动物模型。

Objective To establish a Hr mutant knockout mouse model to study the function of Hr gene. Methods Transcription activator-like effector nucleases（ TALENs） technique was used to disrupt the mouse Hr locus,creating heritable mutations that eliminate Hr function to explore the effects of Hr on hair development and provide a good model to study the function of Hr gene. The phenotype of Hr^（-/-） mice was observed after birth and skin histology of the transgenic mice was studied by light microscopy. Results It was shown that a F0 mouse with the 2- bp deletion in Hr gene ranging from 86 to 87 base pairs was obtained. The male mice with clear deletion of the Hr fragment and with obvious frame shifting were mated with wild-type female mice,and F1 mice were achieved. The heterozygous males mated with females to generate the F2 homozygous mice. The first hair coat of Hr^（-/-） mice developed normally. Beginning from 14 days after birth,however,there was a rapid hair loss. The mices were completely hairless except for a few vibrissae at 30 days.Histologically,two characteristic structures appeared,the utriculus and dermal cyst. Conclusions The results suggest that Hr^（-/-） mice are successfully created using TALENs,and Hr is important for regulating hair development,which could explain at least in part the hair loss and be applied to study the mechanism of hair growth and development disorder.