Transcriptional control of the Cell Cycle in Arabidopsis thaliana

COOLS, T.; DE VEYLDER, L; BREAKFIELD, NW; PALATNIK, JAVIER F.; GOLDY, CAMILA; BENFEY, PN; RODRIGUEZ, RAMIRO E.

Nagoya

Workshop; EMBO Practical course: Functional live imaging of plants; 2019

European Molecular Biology Organization (EMBO)

Plant organ growth occurs through an initial stage of cell proliferation followed by another of expansion and differentiation. The control of the cell cycle (CC) is central for generating organs with defined sizes and morphologies. CC regulators often have an oscillating activity established by transcriptional and posttranscriptional mechanisms of regulation. Several periodic transcriptional regulators have been identified and characterized. Among them, transcription factors (TFs) from the E2F and MYB3Rs families have been described as main regulators of the G1/S and G2/M transitions.Genomic studies indicated that only a subset of the genes with expression peaks at the G1/S or G2/M phases of the CC are directly regulated by these regulators, suggesting that other transcriptional regulators remain to be identified. The objective of our work is to identify and characterize genes that control the CC using Arabidopsis thaliana as a model system.To identify genes that regulate the CC activity, we first analyzed the transcriptome of mitotic cells obtained by fluorescence activated cell sorting. Analysis of these data yielded ca. 20 TFs with expression enriched in these cells. For some of this TFs we confirmed the typical periodic expression expected for CC regulators. To analyze their function, we prepared mutants, dominant repressors, inducible constructs and reporters of the TFs fused to fluorescent proteins that were extensively characterized by LSCM. These approaches enabled us to identify new potential regulators of the CC at the transcriptional level.