Unraveling Male Infertility: Discovery of the Missing Gene

The MC2 protein has been identified as a crucial component in sperm formation, particularly in establishing a functional connection between the head and tail of sperm cells. This discovery, primarily based on experiments conducted on mice, comes from researchers at the University of Gothenburg and has significant implications for understanding male infertility.

The role of the MC2 protein is fundamental in enabling the sperm’s head and tail to connect effectively, a process essential for the coordinated movement necessary for fertilization. This connection is located in what is termed the ‘neck’ of the sperm head. The absence of this connection, as observed in the experiments, leads to complete infertility in male mice. This breakthrough finding is particularly notable because it sheds light on the previously unknown causes of certain types of male infertility, such as acephalic spermatozoa syndrome, where sperm lacks a head.

The production of the MC2 protein is regulated by a specific gene in the genome. When researchers employed gene-editing techniques to remove this gene, the mice stopped producing the protein, leading to infertility. This aspect of the research highlights the role of genetic factors in male infertility, which account for approximately 15 to 30 percent of infertility cases in men.

Furthermore, the gene responsible for the production of the MC2 protein does not reside on the sex chromosome, indicating that its effects are exclusive to male fertility and do not impact the females’ ability to produce offspring. This specificity opens potential avenues for developing targeted treatments for male infertility, as well as the intriguing possibility of creating a male contraceptive method by temporarily inhibiting this gene.

The study, spearheaded by Kexin Zhang, a PhD student at the Department of Chemistry and Molecular Biology, has identified a crucial protein, named “MC2”, which is pivotal in the formation of motile sperm in mice.

The Vital Role of MC2 in Sperm Formation

The research reveals that the MC2 protein is essential for forming a functional connection between the head and tail of sperm cells. This connection, located in the sperm’s “neck,” is critical for the coordinated movement required for successful fertilization. “Without this connection, the sperm’s head and tail, despite being perfectly formed, fail to achieve their purpose, as they cannot reach the egg,” explains Kexin Zhang.

Gene Scissors and Infertility

Through meticulous experimentation involving gene modification in mice, Zhang and her team discovered that the production of MC2 is regulated by a specific gene in the genome. When this gene was altered using gene-editing techniques, the mice ceased producing MC2, leading to complete infertility. This finding is particularly significant as genetic factors are known to account for 15-30% of infertility cases in men.

Interestingly, this gene does not reside on the sex chromosome and therefore does not affect females’ reproductive capabilities.

Broader Implications of the Research

Kexin Zhang’s research not only provides a deeper understanding of male infertility, particularly in cases of acephalic spermatozoa syndrome but also opens doors to new diagnostic and treatment methods. “Approximately 15% of heterosexual couples face challenges in conceiving, with male factors being responsible in about half of these cases. Our research brings hope for novel treatments and diagnostic approaches,” says Zhang.

Furthermore, the study hints at the possibility of developing a male contraceptive by targeting this gene, offering a new avenue in birth control methods.

reference link : https://www.gu.se/nyheter/saknad-gen-kan-forklara-infertilitet