Sequence-specific binding of poly(ADP-ribose) polymerase-1 to the human T cell leukemia virus type-I tax responsive element.
We have previously identified poly(ADP-ribose) polymerase-1 (PARP-1) as a coactivator for the human T cell leukemia virus type I (HTLV-I) transcription activator Tax. While PARP-1 is believed to contribute to DNA repair, PARP-1 has been described as a coactivator for other transcription factors. Recent evidence suggests that PARP-1 forms complexes on cellular promoters, so we investigated PARP-1 complexes on the HTLV-I Tax responsive elements (TxREs) using an end-blocked DNA binding assay. We observed sequence-specific binding of PARP-1 to the TxREs. The DNA binding domain of PARP-1 was fused to the transcriptional activation domain of VP16, and this fusion protein activated the HTLV-I promoter in a TxRE-dependent manner. Internal, sequence-specific binding of PARP-1 to DNA provides a mechanism for transcriptional regulation of the HTLV-I promoter. The mechanism of PARP-1 function in the HTLV-I system may have common mechanistic steps with other cellular promoters, including the formation of active complexes on the promoter.
Zhang
Zhan
Z
Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA.
Hildebrandt
Ellen F
EF
Simbulan-Rosenthal
Cynthia M
CM
Anderson
Mark G
MG
D000818:Animals; D002460:Cell Line; D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral; D016356:Gene Products, tax / Q000235:genetics / Q000378:metabolism*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020218:Response Elements; D014158:Transcription, Genetic
D016356:Gene Products, tax; D011065:Poly(ADP-ribose) Polymerases