title: Variant forms of upstream stimulatory factors (USFs) control the promoter activity of hTERT, the human gene encoding the catalytic subunit of telomerase.
abstract: It is known that Myc regulates the expression of TERT, the telomerase catalytic subunit gene, by binding to E box. Here we show that another E box-binding protein, upstream stimulatory factor (USF), also regulates TERT expression. Specifically, the N-terminally truncated form of USF2 is present in telomerase-negative/resting human lymphocytes, but not in telomerase-positive/phytohemagglutinin-activated lymphocytes. In electrophoretic mobility shift assay, both full-length and truncated USF2s bound to the TERT E box. In a transient expression assay, the truncated USF had a dominant-negative effect on both exogenous full-length USF and endogenous positive regulators for activating TERT expression. These results suggest that the differential abundance of truncated USF2 may regulate telomerase activity during lymphocyte activation.
authors.affiliation: Laboratory of Molecular and Cellular Assembly, Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Yago
authors.forename: Rieko
authors.initials: R
authors.lastname: Ohki
authors.forename: Shinji
authors.initials: S
authors.lastname: Hatakeyama
authors.forename: Toshiro
authors.initials: T
authors.lastname: Fujita
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Ishikawa
mesh_terms: D001665:Binding Sites; D015153:Blotting, Western; D002478:Cells, Cultured; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D024202:Electrophoretic Mobility Shift Assay; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051720:Upstream Stimulatory Factors
chemical_list: D004268:DNA-Binding Proteins; D014157:Transcription Factors; C497181:USF1 protein, human; C497184:USF2 protein, human; D051720:Upstream Stimulatory Factors; D004247:DNA; C509186:TERT protein, human; D019098:Telomerase