title: Association of transcription factor YY1 with the high molecular weight Notch complex suppresses the transactivation activity of Notch.
abstract: Notch receptors are evolutionarily conserved from Drosophila to human and play important roles in cell fate decisions. After ligand binding, Notch receptors are cleaved to release their intracellular domains. The intracellular domains, the activated form of Notch receptors, are then translocated into the nucleus where they interact with other transcriptional machinery to regulate the expression of cellular genes. To dissect the molecular mechanisms of Notch signaling, the cellular targets that interact with Notch1 receptor intracellular domain (N1IC) were screened. In this study, we found that endogenous transcription factor Ying Yang 1 (YY1) was associated with exogenous N1IC in human K562 erythroleukemic cells. The ankyrin (ANK) domain of N1IC and zinc finger domains of YY1 were essential for the association of N1IC and YY1 according to the pull-down assay of glutathione S-transferase fusion proteins. Furthermore, both YY1 and N1IC were present in a large complex of the nucleus to suppress the luciferase reporter activity transactivated by Notch signaling. The transcription factor YY1 indirectly regulated the transcriptional activity of the wild-type CBF1-response elements via the direct interaction of N1IC and CBF1. We also demonstrated the association between endogenous N1IC and intrinsic YY1 in human acute T-cell lymphoblastic leukemia cell lines. Taken together, these results indicate that transcription factor YY1 may modulate Notch signaling via association with the high molecular weight Notch complex.
authors.affiliation: Graduate Institute of Cell and Molecular Biology, Center for Stem Cells Research at Wan-Fang Hospital, Taipei Medical University, Taipei 110, Taiwan. cmbtsyeh@tmu.edu.tw
authors.forename: Tien-Shun
authors.initials: TS
authors.lastname: Yeh
authors.forename: Yu-Min
authors.initials: YM
authors.lastname: Lin
authors.forename: Rong-Hong
authors.initials: RH
authors.lastname: Hsieh
authors.forename: Min-Jen
authors.initials: MJ
authors.lastname: Tseng
mesh_terms: D030161:Avian Proteins; D001665:Binding Sites; D045744:Cell Line, Tumor; D050981:Erythroid-Specific DNA-Binding Factors; D051858:Forkhead Transcription Factors; D017930:Genes, Reporter; D006801:Humans; D020014:K562 Cells; D015513:Oncogene Proteins; D010449:Peptide Mapping; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D014157:Transcription Factors / Q000378:metabolism* / Q000502:physiology*; D015533:Transcriptional Activation; D014764:Viral Proteins; D050986:YY1 Transcription Factor
chemical_list: D030161:Avian Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D051858:Forkhead Transcription Factors; C497761:NOTCH1 protein, human; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D014157:Transcription Factors; D014764:Viral Proteins; D050986:YY1 Transcription Factor; C494698:YY1 protein, human; C490425:v-qin protein, Avian sarcoma virus 31