Artificial recruitment of Sp1 or TBP can replace the role of IE1 in the synergistic transactivation by IE1 and IE2.
The IE1 and IE2 proteins of human cytomegalovirus transactivate various viral and cellular promoters in a synergistic manner, but the mechanism of their action has not been well elucidated. Here we have examined the IE1-IE2 synergy by artificial recruitment of either Sp1 or TBP to the promoter. We found that in the presence of Sp1, the synergistic effect of IE1 on IE2-mediated transactivation dramatically decreased. Furthermore, a 117-amino acids glutamine-rich fragment of Sp1, which can interact with dTAF(II)110 and hTAF(II)130, was sufficient to replace the role of IE1 in IE1-IE2 synergism. It was also found that TBP recruitment to the promoter markedly decreased the synergistic effect of IE1 on IE2-mediated transactivation. These results suggested that in the context of the synergism between IE1 and IE2, the function of IE1 might overlap with that of Sp1, for example by recruiting the TFIID complex.
Kim
J M
JM
Institute for Molecular Biology and Genetics, Seoul National University, Seoul, 151-742, Korea.
Hong
Y
Y
Kim
S
S
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D006224:Cricetinae; D003587:Cytomegalovirus / Q000378:metabolism*; D017874:Immediate-Early Proteins / Q000378:metabolism* / Q000502:physiology; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology*; D014764:Viral Proteins
C088645:IE1 protein, cytomegalovirus; D017874:Immediate-Early Proteins; D016329:Sp1 Transcription Factor; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII; D014764:Viral Proteins