DUX4

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== thumb|right|alt=D4Z4 array diagram|400px|D4Z4 array with three D4Z4 repeats and the 4qA allele {| style="width: 100%; |- | CEN || centromeric end || TEL || [[telomeric end |- | NDE box || non-deleted element || PAS || polyadenylation site |- | triangle || D4Z4 repeat|| trapezoid || partial D4Z4 repeat |- | white box || pLAM || gray boxes || DUX4 exons 1, 2, 3 |- | colspan="4" style="text-align: center; background: #cccdcf;" | arrows |- | corner || promoters || straight || RNA transcripts |- | black || sense || red || antisense |- | blue || DBE-T || dashes || dicing sites |} ]] 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 open reading frame (ORF) is entirely contained within exon 1 and contains two homeoboxes. Exons 2 and 3 encode for the three prime untranslated region (3′-UTR). In certain haplotypes, exon 3 contains a polyadenylation signal. There was no evidence for transcription from the standard cDNA libraries however RT-PCR and in-vitro expression experiments indicate that the ORF is transcribed.