title: Tumor suppressor p53 down-regulates expression of human leukocyte marker             CD43 in non-hematopoietic tumor cells.
abstract: CD43 (leukosialin, sialophorin), a cell surface protein on most hematopoietic             cells, is an important regulator of immune cell function and is involved in regulation             of cell adhesion and proliferation. Aberrant expression of CD43 is a common event             observed in human tumors of non-hematopoietic origin suggesting a role in tumor             development. We have previously shown that overexpression of CD43 causes activation             of the ARF-p53 tumor-suppressor pathway and results in cell death. In a non-functional             ARF-p53 background, the cells overexpressing CD43 display an increased cell growth             rate due to higher survival. Here we show that p53 specifically downregulates             the expression of CD43 at the protein and mRNA level. Transactivating properties             of p53 are necessary to affect the expression of exogenous CD43. The downregulation             of CD43 mRNA is caused by p53-dependent transrepression, at least in part, via             a histone deacetylation mechanism. These studies establish that under certain             conditions there exists a negative feedback loop between p53 and CD43: CD43-dependent             signaling activates p53, which in turn downregulates the expression of CD43.
authors.affiliation: Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia Street 23, 51010 Tartu, Estonia. lkadaja@ebc.ee
authors.forename: Lilian
authors.initials: L
authors.lastname: Kadaja-Saarepuu
authors.forename: Marko
authors.initials: M
authors.lastname: Lõoke
authors.forename: Anna
authors.initials: A
authors.lastname: Balikova
authors.forename: Toivo
authors.initials: T
authors.lastname: Maimets
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D015536:Down-Regulation; D025461:Feedback, Physiological; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006031:Glycosylation; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006655:Histone Deacetylases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007962:Leukocytes / Q000378:metabolism*; D051917:Leukosialin / Q000235:genetics / Q000378:metabolism*; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020871:RNA Stability; D020218:Response Elements; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006877:Hydroxamic Acids; D051917:Leukosialin; C465014:SPN protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C012589:trichostatin A; D008156:Luciferases; D006655:Histone Deacetylases