AIM:To construct and breed infertility model mice with ATP/GTP binding carboxypeptidase 1(Agtpbp1)gene knockout homozygote(Agtpbp1-/-)by CRISPR/Cas9 technology,so as to provide an animal model for the subsequent exploration of the pathogenesis of Agtpbp1 gene in male sterility.METHODS:The CRISPR/Cas9 technology was used to obtain Agtpbp1 gene knockout heterozygote(Agtpbp1+/-)mice according to the data of the main protein functional region of Agtpbp1 gene and combined with Cas9 nuclease.The obtained Agtpbp1+/-mice were mated,and their offspring were genotyped by PCR and agarose gel electrophoresis.The expression of Agtpbp1 at different levels was detected by RT-PCR,Western blot and immunohistochemical staining to support the identification results.The HE staining was used to observe the mouse cerebellum and eyeball structure to analyze the effect of Agtpbp1 gene knockout on Purkinje cells and photoreceptor cells.The symptoms of ataxia in mice were observed in combination with behavioral tests.The growth of mice was observed,and the changes of testicular tissue volume and weight of male mice were analyzed.The HE staining was used to observe the changes of testicular structure,and PAS staining was used to observe the changes of testicular germ cell cycle.Finally,sperm analyzer was used to analyze the sperm motility,so as to analyze the growth and develop-ment of the mice.RESULTS:The male and female Agtpbp1+/-mice could continue to mate,and three genotypes,Agtpbp1 wild-type(Agtpbp1+/+),Agtpbp1+/-and Agtpbp1-/-,were obtained.The genotypes of the offspring mice were successfully identified by PCR.The results of RT-PCR,Western blot and immunohistochemical staining verified the successful con-struction of Agtpbp1-/-mouse model at different levels(P<0.05).The results of HE staining showed that Purkinje cells were lost in the cerebellum of Agtpbp1-/-mice and the number of photoreceptor cells in the eyeball was reduced.Behavioral tests confirmed that Agtpbp1-/-mice had ataxia symptoms such as motor dysfunction and uncoordinated movements.Com-pared with control group,the testicular volume and weight of Agtpbp1-/-mice were significantly reduced.The results of HE staining showed a very small amount of sperm in the testis of Agtpbp1-/-mice.Combined with the sperm analyzer,it was ob-served that the sperm motility,vitality and movement rate of Agtpbp1-/-mice were significantly lower than those of the con-trol mice.Testicular sections with PAS staining showed cell cycle arrest of the sperm from Agtpbp1-/-mice.CONCLU-SION:In this study,Agtpbp1 knockout mice were successfully bred.The deletion of Agtpbp1 caused the arrest of sper-matogenic cell differentiation and the decrease in sperm motility in adult male mice,resulting in infertility.At the same time,it provides a new experimental tool for further exploring the molecular mechanism of Agtpbp1-induced male sterility.

AIM:To construct and breed infertility model mice with ATP/GTP binding carboxypeptidase 1(Agtpbp1)gene knockout homozygote(Agtpbp1-/-)by CRISPR/Cas9 technology,so as to provide an animal model for the subsequent exploration of the pathogenesis of Agtpbp1 gene in male sterility.METHODS:The CRISPR/Cas9 technology was used to obtain Agtpbp1 gene knockout heterozygote(Agtpbp1+/-)mice according to the data of the main protein functional region of Agtpbp1 gene and combined with Cas9 nuclease.The obtained Agtpbp1+/-mice were mated,and their offspring were genotyped by PCR and agarose gel electrophoresis.The expression of Agtpbp1 at different levels was detected by RT-PCR,Western blot and immunohistochemical staining to support the identification results.The HE staining was used to observe the mouse cerebellum and eyeball structure to analyze the effect of Agtpbp1 gene knockout on Purkinje cells and photoreceptor cells.The symptoms of ataxia in mice were observed in combination with behavioral tests.The growth of mice was observed,and the changes of testicular tissue volume and weight of male mice were analyzed.The HE staining was used to observe the changes of testicular structure,and PAS staining was used to observe the changes of testicular germ cell cycle.Finally,sperm analyzer was used to analyze the sperm motility,so as to analyze the growth and develop-ment of the mice.RESULTS:The male and female Agtpbp1+/-mice could continue to mate,and three genotypes,Agtpbp1 wild-type(Agtpbp1+/+),Agtpbp1+/-and Agtpbp1-/-,were obtained.The genotypes of the offspring mice were successfully identified by PCR.The results of RT-PCR,Western blot and immunohistochemical staining verified the successful con-struction of Agtpbp1-/-mouse model at different levels(P<0.05).The results of HE staining showed that Purkinje cells were lost in the cerebellum of Agtpbp1-/-mice and the number of photoreceptor cells in the eyeball was reduced.Behavioral tests confirmed that Agtpbp1-/-mice had ataxia symptoms such as motor dysfunction and uncoordinated movements.Com-pared with control group,the testicular volume and weight of Agtpbp1-/-mice were significantly reduced.The results of HE staining showed a very small amount of sperm in the testis of Agtpbp1-/-mice.Combined with the sperm analyzer,it was ob-served that the sperm motility,vitality and movement rate of Agtpbp1-/-mice were significantly lower than those of the con-trol mice.Testicular sections with PAS staining showed cell cycle arrest of the sperm from Agtpbp1-/-mice.CONCLU-SION:In this study,Agtpbp1 knockout mice were successfully bred.The deletion of Agtpbp1 caused the arrest of sper-matogenic cell differentiation and the decrease in sperm motility in adult male mice,resulting in infertility.At the same time,it provides a new experimental tool for further exploring the molecular mechanism of Agtpbp1-induced male sterility.