Double homeobox, 4 also known as DUX4 is a protein which in humans is encoded by the DUX4 gene. Its misexpression is the cause of facioscapulohumeral muscular dystrophy (FSHD).
Gene
This gene is located within a D4Z4 macrosatellite repeat array in the subtelomeric region of chromosome 4q35. The D4Z4 repeat array contains 11-150 D4Z4 repeats in the general population; a highly homologous D4Z4 repeat array has been identified on chromosome 10. The gene consists of three exons. Exons 1 and 2 are present in each D4Z4 repeat. Only one copy of exon 3 is present, telomeric to the D4Z4 repeat array. The repeat-array and ORF are conserved in other mammals. ==Structure==
Structure
DUX4 protein is 424 amino acids long. DUX4 transcripts can be spliced to produce either DUX4-S (short) or DUX4-FL (full length) mRNAs. DUX4-FL mRNA encodes for the entire DUX4 protein. DUX4-S mRNA encodes for a partial DUX4 protein, which lacks the transcription-activating domain. == Function ==
Function
The DUX4 protein is a transcriptional activator of many genes, one example being paired-like homeodomain transcription factor 1 (PITX1). ==Clinical significance==