General transcription factor that functions at the core of the DNA-binding multiprotein factor TFIID. Binding of TFIID to the TATA box is the initial transcriptional step of the pre-initiation complex (PIC), playing a role in the activation of eukaryotic genes transcribed by RNA polymerase II. Members of the TBP family are differentially required to regulate transcription and development during early embryogenesis. Binds to the promoters of select genes. Belongs to the TFIID complex together with the TBP-associated factors (TAFs). Binds DNA as monomer. Expressed ubiquitously with highest expression in the ovary and testis. The N-terminal domain is extensively phosphorylated. Belongs to the TBP family.