Potential autoregulation of transcription factor PU.1 by an upstream regulatory element

Mol Cell Biol. 2005 Apr;25(7):2832-45. doi: 10.1128/MCB.25.7.2832-2845.2005.

Abstract

Regulation of the hematopoietic transcription factor PU.1 (Spi-1) plays a critical role in the development of white cells, and abnormal expression of PU.1 can lead to leukemia. We previously reported that the PU.1 promoter cannot induce expression of a reporter gene in vivo, and cell-type-specific expression of PU.1 in stable lines was conferred by a 3.4-kb DNA fragment including a DNase I hypersensitive site located 14 kb upstream of the transcription start site. Here we demonstrate that this kb -14 site confers lineage-specific reporter gene expression in vivo. This kb -14 upstream regulatory element contains two 300-bp regions which are highly conserved in five mammalian species. In Friend virus-induced erythroleukemia, the spleen focus-forming virus integrates into the PU.1 locus between these two conserved regions. DNA binding experiments demonstrated that PU.1 itself and Elf-1 bind to a highly conserved site within the proximal homologous region in vivo. A mutation of this site abolishing binding of PU.1 and Elf-1 led to a marked decrease in the ability of this upstream element to direct activity of reporter gene in myelomonocytic cell lines. These data suggest that a potential positive autoregulatory loop mediated through an upstream regulatory element is essential for proper PU.1 gene expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • B-Lymphocytes / metabolism
  • Base Sequence
  • Binding Sites
  • Cell Lineage
  • Gene Expression Regulation / genetics*
  • Humans
  • Mice
  • Mice, Transgenic
  • Molecular Sequence Data
  • Mutation / genetics
  • Myeloid Cells / metabolism
  • Organ Specificity
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins / metabolism*
  • Response Elements / genetics*
  • Sequence Alignment
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism*

Substances

  • Proto-Oncogene Proteins
  • Trans-Activators
  • proto-oncogene protein Spi-1