caa a22 4500 467893942 CHVBK 20180406152757.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s11103-005-4066-1 doi (NATIONALLICENCE)springer-10.1007/s11103-005-4066-1 Natural Synchronisation for the Study of Cell Divisionin the Green Unicellular Alga Ostreococcus tauri [Elektronische Daten] [Benoît Farinas, Camille Mary, Carmem-Lara de O Manes, Yvonne Bhaud, Gérard Peaucellier, Hervé Moreau] Ostreococcus tauri (Prasinophyceae) is a marine unicellular green alga which diverged early in the green lineage. The interest of O. tauri as a potential model to study plant cell division is based on its key phylogenetic position, its simple binary division, a very simple cellular organisation and now the availability of the full genome sequence. In addition O. tauri has a minimal yet complete set of cell cycle control genes. Here we show that division can be naturally synchronised by light/dark cycles and that organelles divide before the nucleus. This natural synchronisation, although being only partial, enables the study of the expression of CDKs throughout the cell cycle. The expression patterns of OtCDKA and OtCDKB were determined both at the mRNA and protein levels. The single OtCDKA gene is constantly expressed throughout the cell cycle, whereas OtCDKB is highly regulated and expressed only in S/G2/M phases. More surprisingly, OtCDKA is not phosphorylated at the tyrosine residue, in contrast to OtCDKB which is strongly phosphorylated during cell division. OtCDKA kinase activity appears before the S phase, indicating a possible role of this protein in the G1/S transition. OtCDKB kinase activity occurs later than OtCDKA, and its tyrosine phosphorylation is correlated to G2/M, suggesting a possible control of the mitotic activity. To our knowledge this is the first organism in the green lineage which showed CDKB tyrosine phosphorylation during cell cycle progression. Springer, 2006 cyclin-dependent kinases nationallicence green alga nationallicence histone H1 kinase activity nationallicence Ostreococcus tauri nationallicence phosphorylation nationallicence synchronisation of the cell division nationallicence Farinas Benoît Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut Mary Camille Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut de O Manes Carmem-Lara Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut Bhaud Yvonne Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut Peaucellier Gérard Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut Moreau Hervé Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut Plant Molecular Biology Kluwer Academic Publishers 60/2(2006-01-01), 277-292 0167-4412 60:2<277 2006 60 11103 https://doi.org/10.1007/s11103-005-4066-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11103-005-4066-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Farinas Benoît Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut NATIONALLICENCE 700 1- Mary Camille Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut NATIONALLICENCE 700 1- de O Manes Carmem-Lara Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut NATIONALLICENCE 700 1- Bhaud Yvonne Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut NATIONALLICENCE 700 1- Peaucellier Gérard Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut NATIONALLICENCE 700 1- Moreau Hervé Laboratoire Arago, Observatoire Océanologique, UMR 7628 CNRS - Université ParisVI, BP44, 66651, France aut NATIONALLICENCE 773 0- Plant Molecular Biology Kluwer Academic Publishers 60/2(2006-01-01), 277-292 0167-4412 60:2<277 2006 60 11103 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer