Stem cell regulation: conserved pluripotency, transcriptional, and metabolic networks in animals and plants

Animal and plant stem cells have evolved lineage-specific regulatory networks over billions of years of independent evolution. However, their shared unicellular origin implies the preservation of shared ancestral regulatory modules and the repeated use of analogous molecular logic in stem cell control. Therefore, this narrative review aims to explore the molecular mechanisms common to animal and plant stem cells by focusing on three key aspects: stemness maintenance, transcriptional regulation, and metabolic control. In terms of stemness maintenance, the review highlights the pivotal functions of conserved proteins including breast cancer gene 1-associated really interesting new gene domain 1 (BARD1; animal protein)/AtROW1 (BARD1 plant homolog), retinoblastoma protein (RB; animal protein)/RETINOBLASTOMA-RELATED (RBR; RB plant homolog), and P-element induced wimpy testis (Piwi; animal protein)/ZWILLE (ZLL; Piwi plant homolog). In terms of transcriptional regulation, the review reveals the conserved functions of complexes and factors, such as Polycomb group PcG/Trithorax group proteins TrxG, switch/sucrose non-fermentable, MYC proto-oncogene (c-Myc; animal protein)/MYC (c-Myc plant homolog), Lin28/cold-shock domain protein 1, and Pumilio RNA-binding proteins in determining stem cell fate. In terms of metabolic regulation, the review delineates the convergent roles of threonine metabolism, target of rapamycin kinase signaling, glycogen synthase kinase (GSK3β; animal protein)/BRASSINOSTEROID-INSENSITIVE 2 (BIN2; GSK3β plant homolog), and nitric oxide signaling in orchestrating stem cell homeostasis by integrating nutrient and environmental signals. Despite vast differences in tissues and environments, the review findings suggest that stem cell systems across multicellular life forms share a common ancient molecular language for regulation. Overall, this review not only offers a fresh perspective on the evolution of stem cell mechanisms but also proposes testable hypotheses and conceptual frameworks for future cross-kingdom studies that may, in the long term, inform regenerative medicine research.