Sp1 and Sp3: functional roles

摘要

Sp1 and Sp3 are ubiquitously expressed transcription factors in mammalian cells. These transcription factors are involved in regulating the expression of genes involved in a wide range of biological processes, including differentiation, cell-cycle progression, and oncogenesis. Sp3 is structurally similar to Sp1, with similar affinities for Sp binding sites, and both factors are associated with histone deacetylase (HDAC) 1 and phosphorylated HDAC2. However, there are significant differences between these 2 factors. Sp1 typically functions as an activator. In contrast, Sp3 functions as a transcriptional activator or repressor, depending upon promoter context and chromatin structure. We recently demonstrated that Sp1 and Sp3 occupy different subnuclear sites and exhibit different associations with the nuclear matrix. Throughout the mitotic process, Sp1 and Sp3 are displaced from the condensed chromosomes and are dispersed throughout the cell as separate punctate distributions.