Sp3 (specificity protein 3) belongs to the Sp family of transcription that control expression of a large number of genes implicated in different processes, including cell-cycle-regulated, hormone-induced and housekeeping genes. The functional complexity of Sp3 may be increased by the presence of at least two shorter Sp3 isoforms inaddition to the full-length protein []. Sp3 has the ability to both activate and repress transcription; this dual nature of Sp3 is regulated by SUMOylation []. Sp3 can interact with and recruit a large number of proteins including the transcription initiation complex, histone modifying enzymes and chromatin remodeling complexes, which suggests it is an important transcription factor in chromatin remodeling and the regulation of gene expression [].
