The Groucho related gene family regulates the gonadotropin releasing hormone gene through interaction with the homeodomain proteins MSX 1 and OCT 1 . ^^^ Furthermore , GRG proteins interact with two regulators of GnRH transcription , the homeodomain proteins MSX 1 and OCT 1 . ^^^ The long GRG forms enhance MSX 1 repression and counteract OCT 1 activation of the GnRH gene . ^^^