m⁶A Methylases Regulate Myoblast Proliferation, Apoptosis and Differentiation

Area of Science:

• Molecular Biology
• Epigenetics
• Animal Science

Background:

• N6-methyladenosine (m6A) is a crucial epitranscriptomic modification regulating gene expression.
• m6A methylation is known to influence skeletal muscle development, but its specific role in bovine myogenesis remains largely uncharacterized.

Purpose of the Study:

• To investigate the role of m6A methylases (METTL3, METTL14, WTAP) and demethylases (FTO, ALKBH5) in bovine skeletal muscle development and myogenesis.

Main Methods:

• Analysis of m6A methylase gene expression in bovine longissimus dorsi muscle at different ages.
• In vitro study of myogenesis using bovine myoblasts.
• Gene knockdown experiments (FTO, ALKBH5, METTL3, METTL14, WTAP) to assess their effects on myoblast proliferation, apoptosis, and differentiation.

Main Results:

• Expression of demethylases (FTO, ALKBH5) was higher in adult than newborn cattle, while methyltransferases (METTL3, METTL14, WTAP) showed reduced expression.
• All five genes' mRNA expression increased during in vitro myogenesis.
• Knockdown of FTO or METTL3 promoted proliferation, inhibited apoptosis, and suppressed differentiation.
• ALKBH5 knockdown had opposite effects.
• METTL14 knockdown enhanced proliferation and impaired differentiation.
• WTAP knockdown attenuated proliferation and increased apoptosis.

Conclusions:

• m6A methylases are involved in regulating bovine skeletal muscle development.
• A complex regulatory network of m6A methylation likely controls skeletal myogenesis, with individual methylases having distinct roles.