Sp1 transcription factor

Transcription factor Sp1, also known as specificity protein 1* is a protein that in humans is encoded by the SP1 gene.

The protein encoded by this gene is a zinc finger transcription factor that binds to GC-rich motifs of many promoters. The encoded protein is involved in many cellular processes, including cell differentiation, cell growth, apoptosis, immune responses, response to DNA damage, and chromatin remodeling. Post-translational modifications such as phosphorylation, acetylation, glycosylation, and proteolytic processing significantly affect the activity of this protein, which can be an activator or a repressor.

In the SV40 virus, Sp1 binds to the GC boxes in the regulatory region (RR) of the genome.