Cell cycle function of a Medicago sativa A2-type cyclin interacting with a PSTAIRE-type cyclin-dependent kinase and a retinoblastoma protein. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Plant Journal Année : 2000

Cell cycle function of a Medicago sativa A2-type cyclin interacting with a PSTAIRE-type cyclin-dependent kinase and a retinoblastoma protein.

Résumé

In plants multiple A-type cyclins with distinct expression patterns have been isolated and classified into three subgroups (A1-A3), while in animal somatic cells a single type of cyclin A is required for cell-cycle regulation from the S to M phases. We studied the function of an A2-type cyclin from Medicago sativa (Medsa;cycA2) which, in contrast to animal and most plant A-type cyclins, was expressed in all phases of the cell cycle. Using synchronized alfalfa cell cultures and anti-Medsa;CycA2 polyclonal antibodies, we showed that while the mRNA level increased steadily from the late G1 to the G2-M phase, the protein level after a rapid increase in S-phase reached a plateau during the G2 phase. In the yeast two-hybrid system, the Medsa;CycA2 protein interacted with the PSTAIRE-motif-containing cyclin-dependent kinase Cdc2MsA and with the maize retinoblastoma protein. Unexpectedly, the CycA2-associated kinase activity was biphasic: a first activity peak occurred in the S phase while the major one occurred during the G2/M transition, with no apparent dependence upon the actual levels of the Medsa;CycA2 and Cdc2MsA proteins. Immunohistological localization of the cyclin A2 protein by immunofluorescence and immunogold labelling revealed the presence of Medsa;CycA2 in the nucleus of the interphase and prophase cells, while it was undetectable thereafter during mitosis. Together these data suggest that Medsa;CycA2 plays a role both in the S phase and at the G2/M transition.
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Dates et versions

hal-00165283 , version 1 (25-07-2007)

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François Roudier, E. Fedorova, J. Györgyey, A. Feher, S. Brown, et al.. Cell cycle function of a Medicago sativa A2-type cyclin interacting with a PSTAIRE-type cyclin-dependent kinase and a retinoblastoma protein.. Plant Journal, 2000, 23 (1), pp.73-83. ⟨10.1046/j.1365-313x.2000.00794.x⟩. ⟨hal-00165283⟩
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