the fbxl3 protein is also involved in a related feedback loop that regulates the transcription of the "bmal1" gene. "bmal1" expression is regulated by the binding of rev-erbα and rorα proteins to retinoic acid-related orphan receptor response elements (rores) in the "bmal1" promoter region. the binding of the rev-erbα protein to the promoter represses expression, while rorα binding activates expression. fbxl3 decreases the repression of "bmal1" transcription by inactivating the rev-erbα and hdac3 repressor complex.