Octamer-binding protein 1 (Oct-1) is a transcription factor that binds to the octamer motif (5'-ATTTGCAT-3') and activates the promoters of genes for some small nuclear RNAs (snRNA) and of genes for histone H2B and immunoglobulins. Oct-1 modulates transcription transactivation by NR3C1, AR and PGR. In case of human herpes simplex virus (HSV) infection, Oct-1 forms a multiprotein-DNA complex with the viral transactivator protein VP16 and HCFC1 thereby enabling the transcription of the viral immediate early genes.