title: RETINOBLASTOMA-RELATED protein stimulates cell differentiation in the Arabidopsis root meristem by interacting with cytokinin signaling.
abstract: Maintenance of mitotic cell clusters such as meristematic cells depends on their capacity to maintain the balance between cell division and cell differentiation necessary to control organ growth. In the Arabidopsis thaliana root meristem, the antagonistic interaction of two hormones, auxin and cytokinin, regulates this balance by positioning the transition zone, where mitotically active cells lose their capacity to divide and initiate their differentiation programs. In animals, a major regulator of both cell division and cell differentiation is the tumor suppressor protein RETINOBLASTOMA. Here, we show that similarly to its homolog in animal systems, the plant RETINOBLASTOMA-RELATED (RBR) protein regulates the differentiation of meristematic cells at the transition zone by allowing mRNA accumulation of AUXIN RESPONSE FACTOR19 (ARF19), a transcription factor involved in cell differentiation. We show that both RBR and the cytokinin-dependent transcription factor ARABIDOPSIS RESPONSE REGULATOR12 are required to activate the transcription of ARF19, which is involved in promoting cell differentiation and thus root growth.
authors.affiliation: Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Perilli
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Perez-Perez
authors.forename: Riccardo
authors.initials: R
authors.lastname: Di Mambro
authors.forename: Cristina Llavata
authors.initials: CL
authors.lastname: Peris
authors.forename: Sara
authors.initials: S
authors.lastname: Díaz-Triviño
authors.forename: Marta
authors.initials: M
authors.lastname: Del Bianco
authors.forename: Emanuela
authors.initials: E
authors.lastname: Pierdonati
authors.forename: Laila
authors.initials: L
authors.lastname: Moubayidin
authors.forename: Alfredo
authors.initials: A
authors.lastname: Cruz-Ramírez
authors.forename: Paolo
authors.initials: P
authors.lastname: Costantino
authors.forename: Ben
authors.initials: B
authors.lastname: Scheres
authors.forename: Sabrina
authors.initials: S
authors.lastname: Sabatini
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D003583:Cytokinins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D000071677:Histidine Kinase; D018519:Meristem / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C503426:ARF19 protein, Arabidopsis; C519632:ARR12 protein, Arabidopsis; D029681:Arabidopsis Proteins; D003583:Cytokinins; C487568:RBR1 protein, Arabidopsis; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase