Description
Transcription factor Sp4, also known as SPR-1, and HF1B, is a protein that in humans is encoded by the SP4 gene. It is a multigene family of SP proteins. Northern blot analysis shows that it is abundantly expressed as a 7.5-kb message in brain, but barely detectable in other human cell lines. It is an activator protein like SP1. However, in contrast to SP1, Sp4 is not able to act synergistically through adjacent binding sites