ABSTRACT
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.