Genetic Framework of Cyclin-Dependent Kinase Function in Arabidopsis

• Published in: Developmental cell 2012-05, Vol.22 (5), p.1030-1040
• Main Authors: Nowack, Moritz K., Harashima, Hirofumi, Dissmeyer, Nico, Zhao, Xin'Ai, Bouyer, Daniel, Weimer, Annika K., De Winter, Freya, Yang, Fang, Schnittger, Arp
• Format: Article
• Language: English
• Subjects: Arabidopsis; Arabidopsis - embryology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biochemistry, Molecular Biology; Biological and medical sciences; Cdc2 protein; CDC2-CDC28 Kinases - genetics; CDC2-CDC28 Kinases - metabolism; Cell differentiation, maturation, development, hematopoiesis; Cell physiology; Cellular Biology; Cyclin-dependent kinase; Cyclin-Dependent Kinases - genetics; Cyclin-Dependent Kinases - metabolism; Data processing; Development Biology; Differentiation; Evolution; Evolution, Molecular; Flowering; Fundamental and applied biological sciences. Psychology; Genetics; Life Sciences; Microscopy, Electron, Scanning; Mitosis - physiology; Molecular and cellular biology; Molecular biology; Mutation; Plant Roots - embryology; Plant Roots - genetics; Plant Roots - metabolism; Plant Shoots - embryology; Plant Shoots - genetics; Plant Shoots - metabolism; Plants genetics; Reproductive Biology; retinoblastoma; S phase; S Phase - physiology; Sexual reproduction; Stem cells; Vegetal Biology
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2012.02.015

Cyclin-dependent kinases (CDKs) are at the heart of eukaryotic cell-cycle control. The yeast Cdc2/CDC28 PSTAIRE kinase and its orthologs such as the mammalian Cdk1 have been found to be indispensable for cell-cycle progression in all eukaryotes investigated so far. CDKA;1 is the only PSTAIRE kinase in the flowering plant Arabidopsis and can rescue Cdc2/CDC28 mutants. Here, we show that cdka;1 null mutants are viable but display specific cell-cycle and developmental defects, e.g., in S phase entry and stem cell maintenance. We unravel that the crucial function of CDKA;1 is the control of the plant Retinoblastoma homolog RBR1 and that codepletion of RBR1 and CDKA;1 rescued most defects of cdka;1 mutants. Our work further revealed a basic cell-cycle control system relying on two plant-specific B1-type CDKs, and the triple cdk mutants displayed an early germline arrest. Taken together, our data indicate divergent functional differentiation of Cdc2-type kinases during eukaryote evolution. [Display omitted] ► Mutants for CDKA;1, the only PSTAIRE CDK in Arabidopsis, are viable ► cdka;1 mutants show specific cell-cycle and cell-differentiation defects ► The key substrate of CDKA;1 function is the Rb homolog RBR1 ► PSTAIRE and plant-specific CDKs have overlapping functions in both G1/S and G2/M Nowack et al. find that mutants in CDKA;1, the only canonical PSTAIRE cyclin-dependent kinase (CDK) in Arabidopsis, are viable. CDKA;1's primary role during S phase entry is to regulate RBR1, an Rb homolog; however, plant-specific B1-type CDKs and CDKA;1 are partially redundant, sharing multiple roles throughout the cell cycle.