Core Clock Protein Subcellular Dynamics Coordinate Local and Global Circadian Control in Syncytia

Area of Science:

• Molecular Biology
• Chronobiology
• Cell Biology

Background:

• Circadian rhythms are regulated by negative feedback loops common in eukaryotes.
• Cellular mechanisms of circadian clocks are not fully understood, especially in multinucleated (syncytial) systems.

Purpose of the Study:

• To investigate the subcellular and subnuclear dynamics of circadian clock proteins in vivo.
• To understand spatiotemporal regulation of circadian rhythms within a syncytial system.

Main Methods:

• Utilized novel microfluidic systems for in vivo tracking.
• Employed a blind mutant with retained circadian function.
• Simultaneously monitored multiple clock components across circadian cycles.

Main Results:

• Observed dynamic subcellular and subnuclear localization of clock proteins.
• Documented robust cycles in FRQ nuclear localization across all nuclei, despite heterogeneous gene expression.
• Found free diffusion of clock components between nuclei and formation of distinct, dynamic nuclear bodies.

Conclusions:

• Separate nuclear clocks in a syncytium ensure synchronous regulation of cellular activities.
• Nuclear protein dynamics play a crucial role in maintaining circadian rhythmicity in multinucleated cells.