Open AccessIdentification and characterization of a cis-acting element that interferes with glucocorticoid-inducible activation of the mouse mammary tumor virus promoter.
Author(s) -
Hirotoshi Tanaka,
Yu Dong,
Qiao Li,
Sam Okret,
JanÅke Gustafsson
Publication year - 1991
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.88.12.5393
Subject(s) - mouse mammary tumor virus , biology , glucocorticoid receptor , glucocorticoid , transfection , microbiology and biotechnology , transcription factor , hormone response element , nuclear localization sequence , cell culture , transcription (linguistics) , oligonucleotide , virus , gene , virology , endocrinology , biochemistry , genetics , estrogen receptor , linguistics , philosophy , cancer , breast cancer
The rat hepatoma cell line M1.19 is stably infected by the mouse mammary tumor virus (MMTV), and the expression of the virus is induced by glucocorticoid treatment. However, in the 6.10.2 variant of M1.19, an increase in MMTV transcription is hardly detectable upon exposure to hormone. The mechanism of hormone-unresponsiveness in these cells has been unclear. In this study, we show that nuclear extract from 6.10.2 cells contains a specific DNA-binding activity that recognizes a sequence motif extending from positions -163 to -147 on the MMTV promoter. An oligonucleotide probe spanning this region binds a nuclear factor distinct from the glucocorticoid receptor. In vivo competition experiments, where increased amounts of a plasmid containing this element were transfected into 6.10.2 cells, showed a dose-dependent increase in hormonal inducibility of MMTV expression. Together, these results indicate that this sequence motif negatively modulates glucocorticoid-inducible activation of the MMTV promoter. Moreover, we have characterized a nuclear factor that preferentially binds to the coding strand of this element.