Structural analysis of the mouse c-HA-ras gene promoter

Authors

  • Mark Plumb,

    1. Beatson Institute for Cancer Research (MP, FF, AB), Glasgow, Scotland and Institut de Recherches sur le Cancer (J-BT, PD, BB), Lille, France
    Search for more papers by this author
  • Jean-Baptiste Telliez,

    1. Beatson Institute for Cancer Research (MP, FF, AB), Glasgow, Scotland and Institut de Recherches sur le Cancer (J-BT, PD, BB), Lille, France
    Search for more papers by this author
  • Frances Fee,

    1. Beatson Institute for Cancer Research (MP, FF, AB), Glasgow, Scotland and Institut de Recherches sur le Cancer (J-BT, PD, BB), Lille, France
    Search for more papers by this author
  • Pierre Daubersies,

    1. Beatson Institute for Cancer Research (MP, FF, AB), Glasgow, Scotland and Institut de Recherches sur le Cancer (J-BT, PD, BB), Lille, France
    Search for more papers by this author
  • Bernard Bailleul,

    1. Beatson Institute for Cancer Research (MP, FF, AB), Glasgow, Scotland and Institut de Recherches sur le Cancer (J-BT, PD, BB), Lille, France
    Search for more papers by this author
  • Allan Balmain

    Corresponding author
    1. Beatson Institute for Cancer Research (MP, FF, AB), Glasgow, Scotland and Institut de Recherches sur le Cancer (J-BT, PD, BB), Lille, France
    • Beatson Institute for Cancer Research, Cancer Research Campaign, Beatson Laboratories, Garscube Estate, Bearsden, Glasgow, G61 1BD, Scotland
    Search for more papers by this author

Abstract

Previous studies have demonstrated that the mouse c-Harvey ras proto-oncogene (c-Ha-ras,) promoter sequences are GC rich and contain several potential transcription factor SP1 binding sites. We investigated the endonuclease hypersensitivity of this region in nuclei in vitro and whole mouse tissues in vivo and identified a very strong, ubiquitous hypersensitive site covering the proximal promoter sequences. Footprint protection studies using nuclear extracts from various cell types including fibroblasts, erythroid cells, and both normal and transformed epithelial cells revealed a consistent protein-binding pattern. Five protein binding sites were observed, four of which correlated with potential SP1 binding sites. Competition experiments using an oligonucleotide corresponding to a consensus SP1 binding site confirmed that these sequences were indeed bound by the SP1 (or SP1-like) trans-acting factor. In addition, no differences were observed between the footprint patterns obtained using extracts from cells of different lineages or between normal and transformed epithelial cells carrying activated ras genes. The controlling elements responsible for differential c-Ha-ras transcription between cell types or at different stages of carcinogenesis therefore probably lie in other regions of the gene.

Ancillary