The hTAF II 68-TEC fusion protein functions as a strong transcriptional activator.
Human extraskeletal myxoid chondrosarcoma (EMC) is caused by a chromosomal translocation that involves TEC (translocated in extraskeletal myxoid chondrosarcoma), and either EWS (Ewing's sarcoma) or hTAF(II)68 (human TATA-binding protein-associated factor II 68), which generates EWS-TEC or hTAF(II)68-TEC fusion proteins, respectively. Although there has been a great deal of progress in characterizing EWS-TEC, there is relatively little known about the biological function of hTAF(II)68-TEC. We have examined the functional consequences of the fusion of the amino terminal domain (NTD) of hTAF(II)68 to TEC in EMC. The chimeric gene encodes a nuclear protein that binds DNA with the same sequence specificity as parental TEC. Nuclear localization of hTAF(II)68-TEC was dependent on the DNA binding domain, and we identified a cluster of basic amino acids in the DNA binding domain, KRRR, that specifically mediate the nuclear localization of hTAF(II)68-TEC. The transactivation activity of hTAF(II)68-TEC was higher than TEC towards a known target promoter that contained several TEC binding sites. Finally, deletion analysis of hTAF(II)68-TEC indicated that the hTAF(II)68 NTD, and the AF1 and AF2 domains of hTAF(II)68-TEC are necessary for full transactivation potential. These results suggest that the oncogenic effect of the t(9;17) translocation may be due to the hTAF(II)68-TEC chimeric protein and that fusion of the hTAF(II)68 NTD to the TEC protein produces a gain of function chimeric product.
Kim
Sol
S
Laboratory of Molecular and Cellular Biology, Department of Life Science, Sogang University, Seoul, Korea.
Lee
Hye Jin
HJ
Jun
Hee Jung
HJ
Kim
Jungho
J
D015153:Blotting, Western; D001859:Bone Neoplasms / Q000235:genetics; D002813:Chondrosarcoma / Q000235:genetics* / Q000473:pathology; D002886:Chromosomes, Human, Pair 17; D002899:Chromosomes, Human, Pair 9; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D012512:Sarcoma, Ewing / Q000235:genetics* / Q000473:pathology; D035381:TATA-Binding Protein Associated Factors / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014178:Translocation, Genetic
D017931:DNA Primers; C102041:TAF15 protein, human; D035381:TATA-Binding Protein Associated Factors; D014157:Transcription Factors