The protein encoded by this gene is a transcription factor that can bind to the GC promoter region of a variety of genes, including those of the photoreceptor signal transduction system. The encoded protein binds to the same sites in promoter CpG islands as does the transcription factor SP1, although its expression is much more restricted compared to that of SP1. This gene may be involved in bipolar disorder and schizophrenia. [provided by RefSeq, May 2016].