title: Growth inhibition by the tumor suppressor p33ING1 in immortalized and primary cells: involvement of two silencing domains and effect of Ras.
abstract: ING1 was identified as an inhibitor of growth and has been described as a tumor suppressor. Furthermore, the expression of ING1 is induced in senescent cells and antisense ING1 extends the proliferative life span of primary human fibroblasts. Cooperation of p33ING1 with p53 has been suggested to be an important function of ING1 in cell cycle control. Intriguingly, it has been shown that p33ING1 is associated with histone acetylation as well as with histone deacetylation function. Here we show that p33ING1 is a potent transcriptional silencer in various cell types. However, the silencing function is independent of the presence of p53. By use of deletion mutants two potent autonomous and transferable silencing domains were identified, but no evidence of an activation domain was found. The amino (N)-terminal silencing domain is sensitive to the histone deacetylase inhibitor trichostatin A (TSA) whereas the carboxy-terminal silencing function is resistant to TSA, suggesting that p33ING1 confers gene silencing through both HDAC-dependent and -independent mechanisms. Interestingly, the presence of oncogenic Ras, which is able to induce premature senescence, increases the p33ING1-mediated silencing function. Moreover, ING1-mediated silencing was reduced by coexpressing dominant-negative Ras or by treatment with the mitogen-activated protein kinase inhibitor PD98059 but not by treatment with SB203580, an inhibitor of the p38 pathway. In addition, we show that both silencing domains of ING1 are involved in cell cycle control, as measured by inhibition of colony formation of immortalized cells and by thymidine incorporation of primary human diploid fibroblasts (HDF). Interestingly, p33ING1 expression induces features of cellular senescence in HDFs.
authors.affiliation: Genetic Institute, Justus-Liebig-University, Heinrich-Buff-Ring 58-62, 35392 Giessen, Germany.
authors.forename: Frauke
authors.initials: F
authors.lastname: Goeman
authors.forename: Dorit
authors.initials: D
authors.lastname: Thormeyer
authors.forename: Maria
authors.initials: M
authors.lastname: Abad
authors.forename: Manuel
authors.initials: M
authors.lastname: Serrano
authors.forename: Oliver
authors.initials: O
authors.lastname: Schmidt
authors.forename: Ignacio
authors.initials: I
authors.lastname: Palmero
authors.forename: Aria
authors.initials: A
authors.lastname: Baniahmad
mesh_terms: D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002460:Cell Line; D002645:Chickens; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D017353:Gene Deletion; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D012190:Retroviridae / Q000235:genetics; D015398:Signal Transduction; D013936:Thymidine / Q000378:metabolism; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D006877:Hydroxamic Acids; C501503:ING1 protein, human; D007093:Imidazoles; C501505:Ing1 protein, mouse; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011725:Pyridines; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C012589:trichostatin A; D018631:ras Proteins; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D013936:Thymidine