DUX4

DUX4

Schematic of the D4Z4 locus on chromosome 4.

DUX4 is a gene located on chromosome 4 in humans. It is part of the D4Z4 repeat array, which is a region of repetitive DNA sequences. The DUX4 gene is known for its role in the pathogenesis of facioscapulohumeral muscular dystrophy (FSHD), a genetic muscle disorder.

Structure

The DUX4 gene is embedded within the D4Z4 repeat array, which consists of multiple tandem repeats. Each repeat unit is approximately 3.3 kilobases in length. The DUX4 gene is located at the distal end of the D4Z4 array and is transcribed from the last repeat unit.

Function

DUX4 encodes a transcription factor that is normally expressed during early embryogenesis. It plays a role in the regulation of gene expression during early development. In healthy individuals, DUX4 expression is tightly controlled and is typically silenced in adult tissues.

Role in Disease

In individuals with FSHD, there is a contraction of the D4Z4 repeat array, leading to the inappropriate expression of the DUX4 gene in muscle cells. This aberrant expression of DUX4 is toxic to muscle cells and leads to the progressive muscle weakness and wasting characteristic of FSHD.

Mechanism of Pathogenesis

The pathogenesis of FSHD involves the loss of epigenetic repression at the D4Z4 locus, allowing for the expression of the DUX4 gene. The toxic effects of DUX4 expression in muscle cells include the activation of apoptosis and the disruption of normal muscle cell function.

Research and Therapeutic Approaches

Research into DUX4 and its role in FSHD is ongoing. Therapeutic approaches aim to silence the expression of DUX4 or to mitigate its toxic effects in muscle cells. Strategies include the use of antisense oligonucleotides, gene therapy, and small molecule inhibitors.

Related Pages

• Facioscapulohumeral muscular dystrophy
• Chromosome 4
• Gene expression
• Transcription factor