Panel A: A schematic shows multinucleated hyphae, in which FRQ sharing between nuclei restores rhythmic luciferase expression and circadian rhythmicity in mutants. Panel B: Comparison of subjective dawn and dusk, showing altered WCC body mobility and interactions with FRQ bodies during circadian regulation. At subjective dawn, WCC binds to DNA, reducing its mobility. At subjective dusk, FRQ body intensity increases, and WCC binds to highly mobile FRQ bodies, increasing WCC body mobility.
Core circadian proteins are shared between local nuclei and form dynamic nuclear bodies across circadian cycles. (A) Schematic representation of the heterokaryon reporter system. As core clock components are shared across nuclei, forming heterokaryons between nuclei with WT circadian proteins and “clockless” nuclei that lack the FRQ gene but contain a frqcbox-luc reporter generates heterokaryotic hyphae with restored circadian rhythmicity in luciferase expression. (B) Model showing how WCC and FRQ body colocalization and mobility may correlate with subjective dawn and dusk. WCC and FRQ form dynamic nuclear bodies. At subjective dawn, WCC binds to DNA. This physical constraint reduces WCC body mobility. WCC drives the expression of FRQ. At subjective dusk, FRQ body intensity increases. WCC then binds to highly mobile FRQ bodies, releasing WCC from DNA, leading to increased WCC body mobility.