title: Embryonic Expression and Function of theXenopusInk4d Cyclin D-Dependent Kinase Inhibitor.
abstract: Here we report the cloning and functional characterization of the cyclin D-dependent kinase 4 and 6 (Cdk4/6) inhibitory protein Cdkn2d/p19Ink4dofXenopuslaevis(Xl-Ink4d).Xl-Ink4dis the onlyInk4family gene highly expressed duringXenopusdevelopment and its transcripts were detected maternally and during neurulation. TheXl-Ink4d protein has 63% identity to mouse and human Cdkn2d/p19Ink4dand its function as a negative regulator of cell cycle traverse is evolutionary conserved. Indeed,Xl-lnk4d can functionally substitute for mouse Cdkn2d in binding to mouse Cdk4 and inhibiting cyclin-D1-dependent CDK4 kinase activity. Further, enforced expression ofXl-lnk4d arrests mouse fibroblasts in the G1 phase of the cell cycle. These findings indicate that CDKN2d/p19Ink4dis conserved through vertebrate evolution and suggestXl-lnk4d may contribute to the development ofXenopuslaevis.
authors.affiliation: Department of Pathology, St. Jude Children's Research Hospital, TN, USA.
authors.forename: Joanne R
authors.initials: JR
authors.lastname: Doherty
authors.affiliation: Department of Biochemistry St. Jude Children's Research Hospital, TN, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Nilsson
authors.affiliation: Department of Tumor Cell Biology, St. Jude Children's Research Hospital, TN, USA.
authors.forename: Emin
authors.initials: E
authors.lastname: Kuliyev
authors.affiliation: Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, FL, USA.
authors.forename: Haiqing
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Sahlgrenska Cancer Center, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Rose
authors.initials: R
authors.lastname: Matthew
authors.forename: John L
authors.initials: JL
authors.lastname: Cleveland
authors.forename: Paul E
authors.initials: PE
authors.lastname: Mead
authors.forename: Martine F
authors.initials: MF
authors.lastname: Roussel
keywords: Cdkn2d; Cell cycle; Cyclin-dependent kinase inhibitor; Ink4d; Xenopuslaevis