Coordinated cell-shape changes control epithelial movement in zebrafish and Drosophila.

Area of Science:

• Developmental Biology
• Cell Biology
• Molecular Biology

Background:

• Epithelial morphogenesis relies on intricate cell shape alterations.
• The precise mechanisms governing these cell shape changes remain incompletely understood.
• Marginal cell shape dynamics are crucial during embryonic events like zebrafish epiboly and Drosophila dorsal closure.

Purpose of the Study:

• To elucidate the conserved molecular mechanisms underlying cell shape changes during epithelial morphogenesis.
• To investigate the roles of actin, myosin 2, and specific kinases in these processes.
• To provide evidence for a shared mechanism across different species.

Main Methods:

• Comparative analysis of epithelial morphogenesis in zebrafish and Drosophila embryos.
• Microscopy techniques to observe actin and myosin 2 localization.
• Genetic analysis to determine the requirement of Ste20-like kinase Msn1 and its Drosophila orthologue Misshapen.

Main Results:

• Identified local recruitment of actin and myosin 2 at the epithelial margin during zebrafish epiboly and Drosophila dorsal closure.
• Demonstrated that marginal cell constriction is dependent on this actin-myosin 2 recruitment.
• Showed that the Ste20-like kinase Msn1 (zebrafish) and Misshapen (Drosophila) are essential for this recruitment process.

Conclusions:

• A conserved mechanism involving localized actin and myosin 2 assembly drives cell shape changes critical for epithelial morphogenesis.
• The Ste20-like kinase Msn1/Misshapen pathway plays a conserved role in regulating this process.
• This finding advances the understanding of fundamental cellular processes in development.