<p>Cell count per cluster and sample.</p>

Single cell RNA-sequencing (scRNA-seq) revealed that the transcriptomes of undifferentiated and differentiating Argk1-depleted myoblasts are not significantly affected compared to control. Furthermore, based on the marker expression and overall composition of scRNA-seq cell clusters, the early states of myoblasts differentiation are not severely disrupted in Argk1-depleted myoblasts. Nonetheless, Argk1 knockdown severely impacts later stages of muscle development.

Remarkably, Argk1-depleted muscles completely lack spontaneous muscle contractions, which are required for proper sarcomere maturation in the formation of the indirect flight muscle. Accordingly, Argk1-depleted muscles showed defects related to sarcomere maturation, and mitochondrial morphogenesis; thus, leading to a severe reduction in muscle growth. Therefore, our data reveal an essential role for Argk1 in flight muscle development, presumably by sustaining local ATP levels to meet the energetic demand to support myofibrillogenesis, muscle growth and proper flight muscle function.</p></div>