New insights into the multiple functions of Sp1, a ubiquitous transcription factor

The eukaryotic transcription factor Sp1 is a sequence-specific DNA-binding protein that binds to GC-rich sequences in a large number of promoters. Des pite its ubiquitous nature, Sp1 (and related factors) can modulate transcri ption of specific genes through interactions with cell type or stage-specif ic transcription factors. Sp1 can also directly influence formation of the transcription initiation complex. Furthermore, binding of Sp1 at distal pro moter elements can affect formation of active chromatin structures. Thus th e Sp1 family of proteins plays a crucial role in gene regulation in higher organisms.