Dual function of a nuclear factor I binding site in MMTV transcription regulation.
AUTOR(ES)
Buetti, E
RESUMO
Using linker-scanning mutagenesis we had previously identified four elements within the MMTV LTR which are necessary for transcriptional stimulation by glucocorticoid hormones. Two of them overlapped with regions to which the glucocorticoid receptor binds in vitro. The third element contained a NF-I binding site, and the fourth the TATA box. Here we show that mutations that abolish in vitro binding of NF-I had a negative effect also on the basal activity of the MMTV promoter of LTR-containing plasmids stably integrated in Ltk- fibroblasts. The analysis of double mutants altered in the NF-I plus either one of the receptor binding elements further demonstrated that the NF-I site functionally cooperated with the proximal (-120) element, which alone was extremely inefficient in stimulation. The stronger distal (-181/-172) element was independent of NF-I and showed functional cooperativity with the proximal hormone-binding element.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=317714Documentos Relacionados
- Nuclear factor I acts as a transcription factor on the MMTV promoter but competes with steroid hormone receptors for DNA binding.
- Ets transcription factor binding site is required for positive and TNF alpha-induced negative promoter regulation.
- Site-specific DNA binding of nuclear factor I: analyses of cellular binding sites.
- Possible function of Ah receptor nuclear translocator (Arnt) homodimer in transcriptional regulation.
- Stimulation of transcription in vitro by binding sites for nuclear factor I.