The sequence-specific transcription factor Sp3 binds GC and GT box sequences in the promoters of a variety of genes. The Sp3 transcription factor contains three zinc finger domains that determine sequence specificity of DNA binding. This transcription factor is thought to regulate nucleoside, nucleotide and nucleic acid metabolism and many other "housekeeping" genes. Sp3 can be modified by sumoylation by Ubc9 and has been shown to interact with other transcription factors and histonbe deacetylases. Sp3 has been reported to act as a transcriptional enhancer and repressor of Sp1 activity in a cell- and context-dependent manner. The Poly6248 antibody recognizes the C-terminal region of human, mouse, and rat Sp3 and has been shown to be useful for Western blotting.