Enhanced proliferation tracer reveals Dorsal-Ventral asymmetry in tracheal epithelial Renewal

Abstract To elucidate spatiotemporal dynamics of tissue renewal, we developed evProTracer, an enhanced dual-recombinase lineage tracing system for cumulative in vivo labeling of proliferating cells. Robust longitudinal tracing using evProTracer in murine tracheal epithelium revealed near-complete homeostatic turnover (91.6 ± 1.29% epithelial replacement over 25 weeks), while basal cell-specific ​Trp63-evProTracer​ uncovered a dorsally biased proliferation pattern​, contributing 33.88 ± 1.44% of total epithelial renewal over 6 months, with early differentiation bias toward club cells. These data demonstrate that ventral epithelial renewal is primarily mediated by non-basal facultative progenitors, revealing their constitutive activation during homeostasis. This study uncovers spatially stratified renewal hierarchies: dorsal basal stem cell reservoirs versus ventral facultative non-basal progenitors. evProTracer provides a versatile platform for investigating tissue plasticity hierarchies in regenerative organs.