Cullin 4-ring finger-ligase plays a key role in the control of endoreplication cycles in Arabidopsis trichomes.

Journal article

One of the predominant cell-cycle programs found in mature tissues is endoreplication, also known as endoreduplication, that leads to cellular polyploidy. A key question for the understanding of endoreplication cycles is how oscillating levels of cyclin-dependent kinase activity are generated that control repeated rounds of DNA replication. The APC/C performs a pivotal function in the mitotic cell cycle by promoting anaphase and paving the road for a new round of DNA replication. However, using marker lines and plants in which APC/C components are knocked down, we show here that outgrowing and endoreplicating Arabidopsis leaf hairs display no or very little APC/C activity. Instead we find that RBX1-containing Cullin-RING E3 ubiquitin-Ligases (CRLs) are of central importance for the progression through endoreplication cycles; in particular, we have identified CULLIN4 as a major regulator of endoreplication in Arabidopsis trichomes. We have incorporated our findings into a bio-mathematical simulation presenting a robust two-step model of endoreplication control with one type of cyclin-dependent kinase inhibitor function for entry and a CRL-dependent oscillation of cyclin-dependent kinase activity via degradation of a second type of CDK inhibitor during endoreplication cycles.

Authors: Roodbarkelari, F; Bramsiepe, J; Weinl, C; Marquardt, S; Novák, B

• Publication status: Published
• Journal: Proceedings of the National Academy of Sciences of the United States of America
• Volume: 107
• Issue: 34
• Pages: 15275-15280
• Publication date: 2010-08-01
• DOI: 10.1073/pnas.1006941107
• EISSN: 1091-6490
• ISSN: 0027-8424
• Language: English
• Keywords: Microscopy, Electron, Scanning; Arabidopsis Proteins; Arabidopsis; DNA Replication; RNA Interference; Carrier Proteins; Plant Structures; Cullin Proteins; Polyploidy; Genes, Plant; Cell Cycle; Plants, Genetically Modified; Mutation; Models, Biological; DNA, Plant