HOXA3(HOMEOBOX A3) is a protein that in humans is encoded by the HOXA3 gene, which is also part of the A cluster on chromosome 7. HOXA3 encodes a DNA-binding transcription factor which may regulate gene expression, morphogenesis, and differentiation. Its cytogenetic location is 7q15.2. In vertebrates, the genes encoding the class of transcription factors called homeobox genes are found in clusters named A, B, C, and D on four separate chromosomes. Expression of these proteins is spatially and temporally regulated during embryonic development. HOXA3 protein is able to complement Hoxd3 deficiency when expressed in the context of the Hoxd3 allele.