Construction and Phenotypic Analysis of Mutant Mice with Partial Deletion of MIWI C-terminal and 3'UTR
Objective To construct mutant mouse with deletion of MIWI protein C-terminal and 3'UTR,and to investigate the effect of partial deletion on the function of MIWI protein.Method Mutant mice with partial deletion of MIWI protein was constructed by CRISPR/Cas9 gene editing technology.Firstly,fertility test was conducted to determine whether the mutation would lead to infertility in male mouse.Secondly,HE staining and other histological method were used to determine the time point of sperm development defects in the male mouse.Finally,the molecular defect of the mutant mice was investigated by Western blot and immunofluorescence staining.Result Fertility test showed that the Miwi+/Del2 heterozygous male mouse was completely infertile,sperm count showed that the total number of sperm decreased by 63%,Western blot showed that the MIWI protein decreased significantly.HE staining of the mutant testis sections showed that round spermatids were abnormal,with significantly increased abnormal sperm(74%).Western blot and immunofluorescence staining results showed that protamine decreased significantly in testis,suggesting that protamine production and/or replacement were affected during sperm deformation,and normal long sperm could not be produced.Conclusion A Miwi+/Del2 heterozygous mouse with partial deletion of Miwi C-terminal and 3'UTR was successfully constructed.Deletion of C-terminal of MIWI protein can lead to male sterility.