Expression, tandem repeat copy number variation and stability of four macrosatellite arrays in the human genome

Background: Macrosatellites are some of the largest variable number tandem repeats in the human genome, but what role these unusual sequences perform is unknown. Their importance to human health is clearly demonstrated by the 4q35 macrosatellite D4Z4 that is associated with the onset of the muscle degenerative disease facioscapulohumeral muscular dystrophy. Nevertheless, many other macrosatellite arrays in the human genome remain poorly characterized. Results: Here we describe the organization, tandem repeat copy number variation, transmission stability and expression of four macrosatellite arrays in the human genome: the TAF11-Like array located on chromosomes 5p15.1, the SST1 arrays on 4q28.3 and 19q13.12, the PRR20 array located on chromosome 13q21.1, and the ZAV array at 9q32. All are polymorphic macrosatellite arrays that at least for TAF11-Like and SST1 show evidence of meiotic instability. With the exception of the SST1 array that is ubiquitously expressed, all are expressed at high levels in the testis and to a lesser extent in the brain. Conclusions: Our results extend the number of characterized macrosatellite arrays in the human genome and provide the foundation for formulation of hypotheses to begin assessing their functional role in the human genome.