Abstract
Rb(retinoblastoma) pathway is thought to play a pivotal role in the regulation of the G1/S transition in animals. Although under- or hypo-phosphorylated Rb represses transactivating ability of E2F/DP transcription family, Rb is inactivated by phosphorylation with cyclin-dependent kinases (CDKs). The resulting hyper-phosphorylated Rb cannot bind to E2F, thereby releasing E2F/DP complex to activate transcription of genes required for entry into S phase.
There has been identified only one Rb-related gene (AtRBR1) in Arabidopsis. It was reported that the homozygous AtRBR1 mutant led to lethal in gametogenesis. We have generated Arabidopsis MM2d cells harboring RNAi of AtRBR1 under the control of estrogen-inducible promoter. As the addition of estrogen resulted in a significant reduction of cell growth, DNA histogram analysis revealed that the population of G1 and G2 cells rapidly increased after treatment with estrogen. We have analyzed the gene expression profile after estrogen induction by the Agilent oligo-DNA microarray.
