Revolutionizing male fertility factor research in mice by using the genome editing tool CRISPR/Cas9

Abstract

BackgroundReproductive research is quintessential in understanding not only the cause of infertility, but also for creating family planning tools. The knockout (KO) system approach is conducive to discovering genes that are essential for fertility in mice. However, in vivo research has been limited due to its high cost and length of time needed to establish KO mice.MethodsThe mechanisms behind the CRISPR/Cas9 system and its application in investigating male fertility in mice are described by using original and review articles.ResultsThe CRISPR/CAS9 SYSTEM has enabled researchers to rapidly, efficiently, and inexpensively produce genetically modified mice to study male fertility. Several genes have been highlighted that were found to be indispensable for male fertility by using the CRISPR/Cas9 system, as well as more complicated gene manipulation techniques, such as point mutations, tag insertions, and double knockouts, which have become easier with this new technology.ConclusionIn order to increase efficiency and usage, new methods of CRISPR/Cas9 integration are being developed, such as electroporation and applying the system to embryonic stem cells. The hidden mysteries of male fertility will be unraveled with the help of this new technology.

Molecular mechanisms of embryonic implantation in mammals: Lessons from the gene manipulation of mice

“…Genome editing systems, such as CRISPR/Cas9, recently became available for the production of knockout animals other than mice . It was shown very recently that genome editing systems are also available for generating conditional knockout animals .…”

“…Genome editing systems, such as CRISPR/Cas9, recently became available for the production of knockout animals other than mice. 117 It was shown very recently that genome editing systems are also available for generating conditional knockout animals. 118 The previous observations from knockout animals are mainly from mice, but many differences exist, even among mammalian species; for example, the source of estrogen secretion, the orientation of the blastocyst for implantation, and the structure of the placenta.…”

CRISPR–Cas9‐mediated mutation revealed BSPH2 protein is dispensable for male fertility

“…To overcome issues of male infertility, it is important to understand all mechanisms related to sperm maturation and fertilization, both in vitro and in vivo (Eskandari-Shahraki, Tavalaee, Deemeh, Jelodar, & Nasr-Esfahani, 2013). In mammals, sperm are produced in the testes, with no ability to swim or fertilize the egg unless two consecutive maturation steps, epididymal maturation and capacitation, occur (Abbasi, Miyata, & Ikawa, 2018;Westmuckett et al, 2014). In epididymal maturation, sperm leave the testes and travel through a convoluted lumen in the epididymis, where they acquire numerous proteins (Aitken, Ryan, Baker, & McLaughlin, 2004;Flesch & Gadella, 2000).…”

Bi-allelic Mutations in TTC21A Induce Asthenoteratospermia in Humans and Mice

“…To further investigate the biological consequences of TTC21A mutations in MMAF-affected men and the roles of TTC21A in sperm flagellar formation, we employed CRISPR-Cas9 technology to generate C57BL/6 mutant mice harboring a Ttc21a frameshift mutation. 30,31 The single-guide RNA (sgRNA) that was used in this study was specifically designed against chr9:119958998-119959075 (GRCm38/mm10) according to the position of the TTC21A stop-gain variant p.Val855*, which is closer to the TTC21A C terminus and might permit the translation of a longer truncated protein than those that are expected from the other two stop-gain variants (p.Ile240* and p.Gln777*) of this study. All experiments involving mice were performed according to the guideline for the care and use of laboratory animals of the US National Institutes of Health.…”