Iroquois homeobox protein 3 (IRX3)

Iroquois homeobox protein 3 (IRX3) is a transcription factor in the Iroquois homeobox gene family, characterized by a homeodomain DNA-binding motif[3][7]. It regulates early steps of neural development and plays roles in the patterning of vertebrate embryos, especially in the central nervous system and heart[3][4][7]. In neural tissue, IRX3 translates morphogen gradients into transcriptional programs to guide neuronal subtype specification[3][6]. In the heart, IRX3 is expressed in the ventricular conduction system, where it regulates expression of gap junction proteins (such as Connexin-40 and Connexin-43) critical for rapid electrical conduction and synchronized ventricular activation[1][3]. Loss of IRX3 function leads to cardiac conduction defects, including arrhythmia phenotypes[1][3]. IRX3 also influences adipocyte differentiation, body mass, and energy homeostasis through epigenetic mechanisms, and genetic variants in regulatory regions between FTO and IRX3 are strongly linked to obesity in humans[3][5]. Aberrant IRX3 expression is found in several leukemia subtypes, where it can drive proliferation and inhibit differentiation of hematopoietic cells[3]. There are no known drugs that directly target IRX3, nor is it currently established as a conventional therapeutic target in clinical practice, although it is of broad research interest in metabolism, neurodevelopment, and cancer biology[2][3][5].

Other names

Iroquois-class homeodomain protein IRX-3IRXB1IRX-1Homeodomain protein IRXB1Iroquois homeobox protein 3