caa a22 4500 47710004X CHVBK 20180405111538.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF00196642 doi (NATIONALLICENCE)springer-10.1007/BF00196642 Cytokinin controls the cell cycle at mitosis by stimulating the tyrosine dephosphorylation and activation of p34cdc2-like H1 histone kinase [Elektronische Daten] [Kerong Zhang, David Letham, Peter John] In excised pith parenchyma from Nicotiana tabacum L. cv. Wisconsin Havana 38, auxin (naphthalene-1-acetic acid) together with cytokinin (6-benzylaminopurine) induced a greater than 40-fold increase in a p34cdc2-like protein, recoverable in the p13suc1-binding fraction, that had high H1 histone kinase activity, but enzyme induced without cytokinin was inactive. In suspension-cultured N. plumbaginifolia Viv., cytokinin (kinetin) was stringently required only in late G2 phase of the cell division cycle (cdc) and cells lacking kinetin arrested in G2 phase with inactive p34cdc2-like H1 histone kinase. Control of the Cdc2 kinase by inhibitory tyrosine phosphorylation was indicated by high phosphotyrosine in the inactive enzyme of arrested pith and suspension cells. Yeast cdc25 phosphatase, which is specific for removal of phosphate from tyrosine at the active site of p34cdc2 enzyme, was expressed in bacteria and caused extensive in-vitro activation of p13suc1-purified enzyme from pith and suspension cells cultured without cytokinin. Cytokinin stimulated the removal of phosphate, activation of the enzyme and rapid synchronous entry into mitosis. Therefore, plants can control cell division by tyrosine phosphorylation of Cdc2 but differ from somatic animal cells in coupling this mitotic control to hormonal signals. Springer-Verlag, 1996 Cell division proteins (cdc2, cdc25, cdk) nationallicence Nicotiana (p34cdc2-like protein) nationallicence Phosphotyrosine nationallicence BAP : 6-benzylaminopurine nationallicence BrdUrd : 5-bromo-2-deoxyuridine nationallicence cdc : cell division cycle nationallicence Cdc25 : cdc phospho-protein phosphatase nationallicence CKI : cyclin dependent kinase inhibitor nationallicence 2,4-D : 2,4-dichlorophenoxyacetic acid nationallicence DAPI : 4′,6′ diamidino-2-phenylindole nationallicence GST-cdc25 : glutathione sulfur transferase-truncated cdc25 fusion nationallicence MS : Murashige and Skoog (1962) nationallicence NAA : naphthalene-1-acetic acid nationallicence p34cdc2 : 34-kDa product of the cdc2 gene nationallicence Zhang Kerong Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, 2601, ACT, Australia aut Letham David Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, 2601, ACT, Australia aut John Peter Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, 2601, ACT, Australia aut Planta Springer-Verlag 200/1(1996-09-01), 2-12 0032-0935 200:1<2 1996 200 425 https://doi.org/10.1007/BF00196642 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00196642 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhang Kerong Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, 2601, ACT, Australia aut NATIONALLICENCE 700 1- Letham David Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, 2601, ACT, Australia aut NATIONALLICENCE 700 1- John Peter Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, 2601, ACT, Australia aut NATIONALLICENCE 773 0- Planta Springer-Verlag 200/1(1996-09-01), 2-12 0032-0935 200:1<2 1996 200 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer