Muscle Growth and the Power of m6A

The process of muscle growth is complex and involves many different factors. One key player is the growth hormone receptor (GHR) mRNA. This receptor is crucial for muscle cells to develop properly. Recently, scientists have been looking into how a specific type of chemical tag, called m6A, affects GHR mRNA. This tag is added to the mRNA by an enzyme called METTL3. Researchers found that when they reduced the amount of GHR in muscle cells, the cells' energy factories, called mitochondria, didn't work as well. This is because the cells couldn't make new mitochondria, a process known as mitochondrial biogenesis. As a result, the muscle cells didn't develop properly. The scientists then looked for places on the GHR mRNA where the m6A tag might be added. They found three potential sites and confirmed that one of them, GHR-139, is indeed tagged by METTL3. This tagging process seems to lower the amount of GHR mRNA and protein in the cell. It also interferes with the signals that the growth hormone sends to the cell, which are important for muscle development. The researchers also found that when they increased the amount of METTL3 in the cells, it lowered the expression of the GHR gene. This also led to a decrease in mitochondrial biogenesis and function. So, it seems that the m6A tagging process is important for regulating the GHR mRNA and, in turn, the development of muscle cells. But how does the m6A tag actually affect the GHR mRNA? The scientists found that it might involve three proteins that can read the m6A tag: hnRNPR, hnRNPA3, and hnRNPM. These proteins might help to control the amount of GHR mRNA in the cell. So, what does all this mean? It seems that the m6A tagging process, which is dependent on the METTL3 enzyme, plays a big role in muscle development. It does this by regulating the GHR mRNA and, in turn, the function of the mitochondria. This is important because the mitochondria are the powerhouses of the cell, providing the energy needed for muscle growth and function. However, there are still many questions left to answer. For example, how exactly do the m6A reader proteins control the GHR mRNA? And what other factors might be involved in this process? These are important questions that future research will need to address.