IRX1 (D5S8Y) Rabbit mAb #14961

The Iroquois-class homeodomain proteins (IRX1-6) comprise a family of transcription factors, initially identified in a mutagenesis experiment in Drosophila designed to identify genes involved in embryonic patterning (1,2). Members of the Iroquois-class protein family contain a three amino acid loop extension (TALE) homeodomain and an IRO sequence motif of unknown function that is unique to this protein family, but which bears similarity to Notch receptor domains involved in protein-protein interactions (3,4). Research studies in various animal models suggest important roles for IRX proteins in early development, including neural patterning, heart field specification, kidney development, and lung development (5-8). Moreover, studies in mice have shown an essential role for IRX proteins in eye development, where they are required for the specification of ommatidia and photoreceptor cells (9).

The human IRX1 gene has been identified as a candidate tumor suppressor (10) that is hypermethylated in a number of cancer subtypes (11). Research studies in head and neck squamous cell carcinoma cell lines specifically suggest that IRX1 interacts with components of the TGFβ signaling pathway to regulate cell proliferation and differentiation (12).