The cellular proto-oncogene product Myb acts as transcriptional activator of the long terminal repeat of human T-lymphotropic virus type I

P. Dasgupta, C. D. Reddy, P. Saikumar, E. P. Reddy

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23 Scopus citations


The proto-oncogene c-myb encodes a nuclear transcription factor that binds to DNA in a sequence-specific manner and activates transcription of several viral and cellular genes. Expression of the c-myb gene is induced in mitogen- and/or antigen-stimulated T lymphocytes, which are also the preferential target cells of human T-lymphotropic virus type I (HTLV-I) in vivo and in vitro. We report here that Myb binds to the HTLV-I long terminal repeat (LTR) in four different regions in a sequence-specific manner. Electrophoretic mobility shift assay using labeled LTR fragments as well as labeled double-stranded oligonucleotides show that there are two high-affinity and two low-affinity Myb-binding sites present in the HTLV-I LTR. DNase I footprinting analysis and oligonucleotide competition experiments indicate that this binding is sequence specific. Cotransfection experiments in HeLa cells, using a Myb expression vector and chloramphenicol acetyltransferase reporter gene linked to the HTLV-I LTR, show that Myb activates HTLV-I LTR-mediated transcription by a factor of four-to sixfold. Thus, in HTLV-I-infected T cells, Myb protein binding to the HTLV-I LTR may constitute one of the signals that regulate HTLV-I transcription in vivo.

Original languageEnglish (US)
Pages (from-to)270-276
Number of pages7
JournalJournal of Virology
Issue number1
Publication statusPublished - Jan 1 1992


ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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