https://scholars.lib.ntu.edu.tw/handle/123456789/186490
標題: | Multifarious Transcriptional Regulation of Adhesion Protein Gene Ap65-1 by a Novel Myb1 Protein in the Protozoan Parasite Trichomonas Vaginalis | 作者: | ONG, SHIOU-JENG HSU, HONG-MING LIU, HSING-WEI TAI, JUNG-HSIANG |
關鍵字: | INITIATOR-BINDING-PROTEIN;DNA-BINDING;PRIMITIVE EUKARYOTE;MOLECULAR CHARACTERIZATION;PROMOTER RECOGNITION;CORE PROMOTER | 公開日期: | 2006 | 卷: | v.5 | 期: | n.2 | 起(迄)頁: | 391-399 | 來源出版物: | EUKARYOTIC CELL | 摘要: | Transcription efficiency of an adhesion protein gene, ap65-1 , in Trichomonas vaginalis varies with changes in the iron supply and growth stages. In the present study, two Myb recognition elements, MRE-1/MRE-2r and MRE-2f, were found to play antagonistic roles in regulating iron- inducible activity of an ap65-1 reporter gene. Intriguingly, either of these elements was shown to be sufficient to repress basal activity, but together they were also shown to activate growth-related activity, of the reporter gene in iron- depleted cells. A myb1 gene, which encodes a 24-kDa open reading frame containing a Myb-like R2R3 DNA binding domain, was identified from Southwestern screening of MRE-2f- binding proteins. The Myb1 protein was detected as a major 35-kDa protein, which exhibited variations in nuclear concentrations with changes in the iron supply. A recombinant Myb1 was shown to differentially interact with MRE-1/MRE-2r and MRE-2f in vitro. Overexpression of a hemagglutinin-tagged Myb1 in T. vaginalis resulted in repression or activation of ap65-1 transcription in iron- depleted cells at an early or a late stage of cell growth, respectively, while iron-inducible ap65-1 transcription was constitutively repressed. The hemagglutinin-tagged Myb1 was found to constantly occupy the chromosomal ap65-1 promoter at a proximal site, but it also selected two more distal sites only at the late growth stage. Together, these observations suggest that Myb1 critically regulates multifarious ap65-1 transcription, possibly via differential selection of multiple promoter sites upon environmental changes. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/93824 |
顯示於: | 醫學系 |
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