Microprotein INducer of fusION (Minion), also called protein myomixer or protein myomerger, is encoded by the MYMX gene. Along with Myomaker, it allows cells to fuse and form multinucleated fibers that are capable of contracting. A lack of Minion disables skeletal muscles, including the diaphragm, resulting in perinatal death in mice. This insight into the Minion-Myomaker system may one day be exploited for targeted drug delivery involving fusing cells in cancer or other contexts. The production of Minion peaks three to four days after injury, similar to the expression profile of Myomaker.
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