cyclin box found in Arabidopsis thaliana retinoblastoma-related protein 1 (AtRBR1) and similar proteins
AtRBR1 is a key regulator of entry into cell division. It acts as a transcription repressor of E2F target genes, whose activity is required for progress from the G1 to the S phase of the cell cycle. AtRBR1 plays a central role in the mechanism controlling meristem cell differentiation, cell fate establishment and cell fate maintenance during organogenesis and gametogenesis. AtRBR1 contains one cyclin box. The cyclin box is a protein binding domain.