Feedback regulation of Notch signaling and myogenesis connected by MyoD-Dll1 axis

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Myoblasts are crucial for muscle development and regeneration.
• Notch signaling is vital for regulating the myogenic program in myoblasts.
• The feedback mechanisms between myogenic cues and Notch activity in myoblasts remain largely unexplored.

Purpose of the Study:

• To investigate how myogenic cues, specifically MyoD, influence Notch signaling in myoblasts.
• To elucidate the molecular mechanisms underlying the interplay between MyoD, Dll1, and Notch signaling during myogenesis.
• To understand the reciprocal control between Notch signaling and myogenesis.

Main Methods:

• Utilized mouse and human gene gain/loss-of-function studies.
• Characterized myogenesis in a novel E-box deficient mouse model.
• Employed CRISPR-mediated interference in human cells to study cis-regulatory elements.
• Investigated the transcriptional regulation of the MyoD-Dll1-Notch axis in vivo and in vitro.

Main Results:

• Demonstrated that MyoD directly induces the expression of the Notch ligand Dll1.
• Showed that MyoD-induced Dll1 activates the Notch pathway in neighboring myoblasts, preventing precocious differentiation.
• Revealed that MyoD autonomously inhibits Notch signaling in Dll1-expressing cells to promote their myogenic program.
• Uncovered key cis-regulatory DNA motifs mediating these reciprocal controls.

Conclusions:

• MyoD plays a dual role in regulating Notch signaling during myogenesis.
• This study reveals a crucial transcriptional mechanism governing the feedback loop between Notch signaling and myogenesis.
• The findings provide new insights into the molecular basis of muscle development and regeneration.