OsCR4, an active receptor-like kinase, plays an essential role in maintaining the interlocking of the palea and lemma by promoting epidermal cell differentiation. Electrophoretic mobility shift assays showed that both OsGRF10 and OsGRF6 proteins bind to the OsCR4 promoter but OsGIF1 enhances the transactivation activity of OsGRF10 to the promoter of CR4 compared with OsGRF10 alone.