HLH-30/TFEB is necessary for chromatin reorganization and maintenance of cell quiescence during starvation in C. elegans.

Cellular quiescence is a low metabolic, non-proliferative state critical for tissue maintenance and regenerative capacity, with broad implications for aging and age-related diseases. In Caenorhabditis elegans, L1 developmental arrest upon hatching in the absence of food provides a robust in vivo model to study quiescence. Here, we investigate the roles of the transcription factors HLH-30/TFEB and DAF-16/FOXO during L1 arrest. We show that HLH-30 and DAF-16 collaborate to ensure survival under starvation, with reciprocal regulation of their subcellular localization and transcriptional activity. HLH-30 exerts broad transcriptional control during L1 arrest, modulating genes involved in chromosome organization and cell cycle progression. Profiling of chromatin spatial distribution reveals that HLH-30 is required for fasting-induced 3D chromatin reorganization. Loss of HLH-30 disrupts seam cell cycle arrest and causes the overactivation of the transcription factors BLMP-1 and CEBP-1, which contribute to premature initiation of developmental programs under starvation. Our findings uncover previously unrecognized functions of HLH-30 in genome architecture and quiescence regulation, highlighting conserved mechanisms of transcriptional control during nutrient deprivation with implications for aging and disease.