Extracellular matrix restrains cell-cycle progression by nuclear exclusion of Yorkie in Drosophila

Area of Science:

• Developmental Biology
• Cell Biology
• Extracellular Matrix Research

Background:

• Tissues and organs achieve a characteristic final size during animal development.
• Cessation of cell-cycle progression is a hallmark of tissues reaching their final size.
• Mechanisms halting cell-cycle progression in mature tissues are not fully understood.

Purpose of the Study:

• To investigate the role of the extracellular matrix (ECM) in halting cell-cycle progression in Drosophila wing discs.
• To elucidate the molecular mechanisms by which ECM influences cell-cycle arrest.
• To determine the necessity of ECM dynamics for tissue growth regulation and organ size control.

Main Methods:

• Utilized Drosophila melanogaster as a model organism, specifically late-larval-stage wing discs.
• Manipulated extracellular matrix (ECM) levels through depletion and increased thickness.
• Assessed cell-cycle progression using G2-phase arrest markers.
• Investigated the role of the co-transcriptional activator Yorkie (YAP/TAZ homolog) and its localization.
• Examined ECM degradation during pupal stages and its impact on cell-cycle resumption and adult wing size.

Main Results:

• Extracellular matrix (ECM) is both necessary and sufficient to halt cell-cycle progression at G2 phase in developing wing discs.
• Depleting ECM causes nuclear accumulation of Yorkie, releasing cells from G2 arrest in a Yorkie-dependent manner.
• Increasing ECM thickness induces premature G2-phase accumulation, which can be overcome by activated Yorkie.
• Programmed ECM degradation is essential for the resumption of cell-cycle progression in pupal stages and for normal adult wing size.

Conclusions:

• The extracellular matrix (ECM) plays a critical role in restraining cell-cycle progression as tissues reach their final size.
• ECM-mediated nuclear exclusion of Yorkie is a key mechanism controlling cell-cycle arrest in developing tissues.
• ECM dynamics, including degradation, are vital for proper tissue growth, cell-cycle regulation, and organ size determination.