The fusion of myoblasts is an important step during skeletal muscle differentiation. A recent study in mice found that a transmembrane protein called Myomaker, which is specifically expressed in muscle, is critical for myoblast fusion. However, the cellular mechanism of its roles and the regulatory mechanism of its expression remain unclear. Chicken not only plays an important role in meat production but is also an ideal model organism for muscle development research. Here, we report that Myomaker is also essential for chicken myoblast fusion. Forced expression of Myomaker in chicken primary myoblasts promotes myoblast fusion, whereas knockdown of Myomaker by siRNA inhibits myoblast fusion. MYOD and MYOG, which belong to the family of myogenic regulatory factors, can bind to a conserved E-box located proximal to the Myomaker transcription start site and induce Myomaker transcription. Additionally, miR-140-3p can inhibit Myomaker expression and myoblast fusion, at least in part, by binding to the 3ʹ UTR of Myomaker in vitro. These findings confirm the essential roles of Myomaker in avian myoblast fusion and show that MYOD, MYOG and miR-140-3p can regulate Myomaker expression.

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In this paper, harmless municipal solid waste incineration fly ash (H-MSWIFA) was used to replace part of the mineral powder in asphalt mastic prepared with different ratios of filler to asphalt (F/A). Cone penetration (CPT), rotational viscosity, low-temperature bending, and full section fracture energy(FSFET) tests on the prepared H-MSWIFA asphalt mastic were carried out to evaluate the viscosity at room temperature, viscosity at high temperature, tensile property at low temperature, and crack resistance at room temperature of the asphalt mastic with different F/A and different H-MSWIFA content. An asphalt concrete mixture with a nominal maximum particle size of 13 mm (AC-13) with different F/A and H-MSWIFA replacement ratios was prepared. The effects of F/A and H-MSWIFA content on the high-temperature stability, water stability, and low-temperature cracking resistance of the asphalt mixture were studied. The results showed that the shear strength and viscosity of the asphalt mastic increased after H-MSWIFA replaced part of the mineral powder; and the greater the F/A, the greater the shear strength and viscosity of the asphalt mastic. H-MSWIFA can greatly improve the viscosity of asphalt mastic at high temperatures, and with the increase in H-MSWIFA content, the improvement effect becomes more obvious. The high-temperature stability of the asphalt mixture is not related to H-MSWIFA content but mainly depends on the F/A. Both the F/A and the H-MSWIFA replacement ratio can significantly affect the water stability of the asphalt mixture, specifically, the water stability reaches the best value when the F/A is around 1.0, and the addition of H-MSWIFA harms water stability. Both the F/A and the H-MSWIFA replacement ratio can significantly affect the low-temperature cracking resistance of the asphalt mixture. The higher the F/A, the worse the low-temperature crack resistance. At the same time, the addition of H-MSWIFA harms low-temperature cracking resistance. From the point of view of water stability and low-temperature crack resistance of the asphalt mixture, the H-MSWIFA replacement ratio should not be too high.