[Gene regulatory networks operated by iron-heme metabolism: focusing on the erythroid differentiation system]

Recently, attention has been focused on how metabolites regulate cellular differentiation. Heme synthesis is greatly enhanced during erythroid differentiation. Heme is used for hemoglobin synthesis, which is needed for oxygen transport by red blood cells. Additionally, several pieces of evidence revealed that heme may control gene expression to fulfill erythroblast terminal maturation. For instance, heme binds to and inactivates the transcription factor BTB Domain And CNC Homolog 1 (BACH1), thereby inducing the globin gene expression, which is the repressive target of BACH1. Moreover, heme induces autophagy/mitophagy-related gene expressions, which are the targets of the transcription factor GATA1 and may promote erythrocyte maturation by itself. Heme may directly bind to guanine tetramer (G-quadruplex) regions of genomic DNA, thereby regulating nearby gene expressions. Here, we present an overview of the mechanism by which iron-heme metabolism regulates gene regulatory networks by focusing on the erythroid differentiation system. Additionally, we discuss the prospects of future research regarding iron-heme metabolism.