CRISPR/Cas9-mediated genome editing reveals 30 testis-enriched genes dispensable for male fertility in mice†

Yonggang Lu,Daiji Kiyozumi,Ayako Isotani,Cristian Coarfa,Tamara Larasati,Qian Zhang,Seiya Oura,Asami Oji,Masaru Okabe,Masahito Ikawa,Caitlin A Huddleston,Tomohiro Tobita,Nobuyuki Sakurai,Takafumi Matsumura,Mayo Kodani,Julio M Castaneda,Taichi Noda,Keisuke Shimada,Haruhiko Miyata,Yoshitaka Fujihara,Martin M Matzuk ,R John Aitken ,Sam Young ,Matthew J Robertson ,Thomas Garcia

doi:10.1093/biolre/ioz103

Abstract

More than 1000 genes are predicted to be predominantly expressed in mouse testis, yet many of them remain unstudied in terms of their roles in spermatogenesis and sperm function and their essentiality in male reproduction. Since individually indispensable factors can provide important implications for the diagnosis of genetically related idiopathic male infertility and may serve as candidate targets for the development of nonhormonal male contraceptives, our laboratories continuously analyze the functions of testis-enriched genes in vivo by generating knockout mouse lines using the CRISPR/Cas9 system. The dispensability of genes in male reproduction is easily determined by examining the fecundity of knockout males. During our large-scale screening of essential factors, we knocked out 30 genes that have a strong bias of expression in the testis and are mostly conserved in mammalian species including human. Fertility tests reveal that the mutant males exhibited normal fecundity, suggesting these genes are individually dispensable for male reproduction. Since such functionally redundant genes are of diminished biological and clinical significance, we believe that it is crucial to disseminate this list of genes, along with their phenotypic information, to the scientific community to avoid unnecessary expenditure of time and research funds and duplication of efforts by other laboratories.

Highlights

One in every six couples is suffering from infertility, with male factors wholly or partly contributing to nearly 50% of overall infertility cases [1, 2]
More than 1000 genes are predicted to be predominantly expressed in mouse testis, yet many of them remain unstudied in terms of their roles in spermatogenesis and sperm function and their essentiality in male reproduction
Since individually indispensable factors can provide important implications for the diagnosis of genetically related idiopathic male infertility and may serve as candidate targets for the development of nonhormonal male contraceptives, our laboratories continuously analyze the functions of testis-enriched genes in vivo by generating knockout mouse lines using the CRISPR/Cas9 system

Summary

Introduction

One in every six couples is suffering from infertility, with male factors wholly or partly contributing to nearly 50% of overall infertility cases [1, 2]. Male infertility is recognized as a complicated pathological condition that is characterized by an extreme heterogeneous spectrum of phenotypic presentations [3]. Such multifactorial nature of etiology hampers the diagnosis of male infertility and renders the underlying causes of reproductive defects obscure in about half of the cases [4]. Genetic disorders emerge as one of the leading causes of male infertility, accounting for at least 15% of male infertility cases and being involved in all four of the major etiologies [5]. The genetic networks underpinning fertility in men should be intensively interrogated for the sake of the reproductive health of male patients and the general well-being of their children [5]

Methods

Results

Conclusion