Withdrawal of differentiation inhibitory activity/leukemia inhibitory factor up-regulates D-type cyclins and cyclin-dependent kinase inhibitors in mouse embryonic stem cells.
The expression of E and D-type cyclins, Cyclin-Dependent Kinase (CDK) 2 and 4, as well as CDK inhibitors p21Cip1 and p27Kip1 were examined during in vitro differentiation of mouse embryonic stem (ES) cells. ES cells cultured in presence of Differentiation Inhibitory Activity/Leukemia Inhibitory Factor (DIA/LIF) express very low levels of cyclin E/CDK2 complexes, p21Cip1 and p27Kip1 CDK inhibitors, while cyclin D/CDK4-associated kinase activity is undetectable. Withdrawal of DIA/LIF, which induces differentiation, results in the progressive up-regulation of all. Up-regulation of D cyclins occurs through an increase in the steady-state levels of mRNA, concomitantly with the activation of Brachyury and Goosecoid, two early markers of mesoderm differentiation. Similarly, cells from the epiblast of the early postimplantation mouse embryo do not express any cyclin D/CDK4 complexes. These are progressively upregulated at gastrulation and early organogenesis. DIA/LIF-stimulated ES cells are not growth-arrested by overexpression of p16Ink4a, a specific inhibitor of CDK4 and CDK6. We propose that the G1/S transition may be regulated by a minimal mechanism in mouse embryonic stem cells. Induction of differentiation triggers the establishment of a more sophisticated mechanism involving both cyclin D/CDK4- and CDK inhibitor-associated control of G1-phase progression.
Savatier
P
P
Laboratoire de Biologie Moléculaire et Cellulaire-UMR 49 CNRS-LA INRA, Ecole Normale Supérieure de Lyon, France.
Lapillonne
H
H
van Grunsven
L A
LA
Rudkin
B B
BB
Samarut
J
J
D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000502:physiology; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D002478:Cells, Cultured; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000096:biosynthesis*; D004622:Embryo, Mammalian / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism*; D016193:G1 Phase; D006131:Growth Inhibitors / Q000502:physiology*; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000502:physiology*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D013234:Stem Cells / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D015854:Up-Regulation
D002352:Carrier Proteins; C493957:Cdkn1a protein, mouse; C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D006131:Growth Inhibitors; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D008222:Lymphokines; D008869:Microtubule-Associated Proteins; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27