title: p53-independent expression of p21Cip1 in muscle and other terminally differentiating cells.
abstract: Terminal differentiation is coupled to withdrawal from the cell cycle. The cyclin-dependent kinase inhibitor (CKI) p21Cip1 is transcriptionally regulated by p53 and can induce growth arrest. CKIs are therefore potential mediators of developmental control of cell proliferation. The expression pattern of mouse p21 correlated with terminal differentiation of multiple cell lineages including skeletal muscle, cartilage, skin, and nasal epithelium in a p53-independent manner. Although the muscle-specific transcription factor MyoD is sufficient to activate p21 expression in 10T1/2 cells, p21 was expressed in myogenic cells of mice lacking the genes encoding MyoD and myogenin, demonstrating that p21 expression does not require these transcription factors. The p21 protein may function during development as an inducible growth inhibitor that contributes to cell cycle exit and differentiation.
authors.affiliation: Department of Biochemistry, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030.
authors.forename: S B
authors.initials: SB
authors.lastname: Parker
authors.forename: G
authors.initials: G
authors.lastname: Eichele
authors.forename: P
authors.initials: P
authors.lastname: Zhang
authors.forename: A
authors.initials: A
authors.lastname: Rawls
authors.forename: A T
authors.initials: AT
authors.lastname: Sands
authors.forename: A
authors.initials: A
authors.lastname: Bradley
authors.forename: E N
authors.initials: EN
authors.lastname: Olson
authors.forename: J W
authors.initials: JW
authors.lastname: Harper
authors.forename: S J
authors.initials: SJ
authors.lastname: Elledge
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002454:Cell Differentiation; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis* / Q000235:genetics; D004622:Embryo, Mammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D017570:MyoD Protein / Q000235:genetics / Q000502:physiology; D018008:Myogenin / Q000235:genetics / Q000502:physiology; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D017570:MyoD Protein; C503801:Myog protein, mouse; D018008:Myogenin; D016159:Tumor Suppressor Protein p53