ssc-mir-21: Ssc-mir-21 is a microRNA that directly regulates endogenous TGFβI protein synthesis during myogenesis, as concluded from in vivo and in vitro experiments [PMC4423774]. In a study, different classes of microRNAs were analyzed for their expression levels at different developmental stages [PMC4423774]. One class, including ssc-mir-21, showed 100-fold greater expression at E90 compared to D100 [PMC4423774]. Other microRNAs in this class were ssc-miR-126, ssc-miR-143-3p, ssc-miR-127, ssc-miR-148a, ssc-miR-196b-5p, and ssc-miR-369 [PMC4423774]. Another class of microRNAs exhibited expression levels slightly lower than 100-fold compared to D100 [PMC4423774]. This class included ssc-miR-542-3p, ssc-miR-99b, ssc-miR-378, ssc-miR-30a-5p, ssc-miR-10b, and ssc-mir-21 [PMC4423774]. These findings provide insights into the differential expression patterns of various microRNAs during myogenesis and highlight the role of specific microRNAs like ssc-mir-21 in regulating protein synthesis [PMC4423774].