B-MYB transactivates its own promoter through SP1-binding sites

Arturo Sala, Biagio Saitta, Pasquale De Luca, Maria N. Cervellera, Ida Casella, Robert E. Lewis, Roger Watson, Cesare Peschle

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

B-MYB is an ubiquitous protein required for mammalian cell growth. In this report we show that B-MYB transactivates its own promoter through a 120 bp segment proximal to the transcription start site. The B-MYB-responsive element does not contain myb-binding sites and gel-shift analysis shows that SP1, but not B-MYB, protein contained in SAOS2 cell extracts binds to the 120 bp B-myb promoter fragment. B-MYB-dependent transactivation is cooperatively increased in the presence of SP1, but not SP3 overexpression. When the SP1 elements of the B-myb promoter are transferred in front of a heterologous promoter, an increased response to B-MYB results. In contrast, c-MYB, the prototype member of the Myb family, is not able to activate the luciferase construct containing the SP1 elements. With the use of an SP1-GAL4 fusion protein, we have determined that the cooperative activation occurs through the domain A of SP1. These observations suggest that B-MYB functions as a coactivator of SP1, and that diverse combinations of myb and SP1 sites may dictate the responsiveness of myb-target genes to the various members of the myb family.

Original languageEnglish (US)
Pages (from-to)1333-1339
Number of pages7
JournalOncogene
Volume18
Issue number6
DOIs
StatePublished - Feb 11 1999

Keywords

  • B-MYB
  • Cell-cycle
  • Promoter
  • SP1
  • Transcription

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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