Double Homeobox Protein 1 (DUX1)

The human genome contains hundreds of repeats of the 3.3-kb family in regions associated with heterochromatin. The DUX gene family, including DUX1, resides within these 3.3-kb repeated elements .

Using RT-PCR amplification of total RNA from human rhabdomyosarcoma cells with primers from HEFT1, a genomic sequence identified as a DNA-binding target of HLTF (SMARCA3), Ding et al. (1998) isolated DUX1. The deduced 170-amino acid protein has a calculated molecular mass of 19.4 kD and contains a double homeobox domain. The first DUX1 homeodomain shares similarity with the PAX3 and PAX7 homeodomains, while the second homeodomain is more similar to those of OTX1 and OTX2. Western blot revealed the presence of 20-kD band in human rhabdomyosarcoma cell extracts.