Role of the TATA box in transcription of the mouse mammary tumor virus long terminal repeat
| Autor: | Philip Kusk, Barbour S. Warren, K E Carlson, Gordon L. Hager |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Transcription
Genetic viruses TATA box Molecular Sequence Data Breast Neoplasms Endocrinology Transcription (biology) Mammary tumor virus Tumor Cells Cultured Humans Promoter Regions Genetic Molecular Biology Repetitive Sequences Nucleic Acid Binding Sites Base Sequence biology General transcription factor Mouse mammary tumor virus Nuclear Proteins Promoter General Medicine biology.organism_classification TATA Box Molecular biology Long terminal repeat Mammary Tumor Virus Mouse DNA Viral HIV Long Terminal Repeat HeLa Cells |
| Zdroj: | Molecular Endocrinology. 9:1180-1192 |
| ISSN: | 1944-9917 0888-8809 |
| Popis: | An in vitro transcription system from mammary cells was established to study transcription of the long terminal repeat (LTR) of the mouse mammary tumor virus (MMTV). Experiments with progressive 5'-deletion constructs of the MMTV LTR revealed that a 19-base pair (bp) region from -41 to -23 bp, encompassing the TATA box and flanking DNA sequence, was as transcriptionally active as larger promoter constructs, both in nuclear extracts from human mammary cell lines (T47D and MCF7) and a nonmammary cell line (HeLa). The cell-free system was capable of supporting transcriptional induction by factors binding upstream of the TATA box, however, since purified glucocorticoid receptor-induced transcription in larger promoter constructs encompassing the MMTV hormone-responsive elements. Transcription from two other promoters, the adenovirus major late promoter and the human immunodeficiency virus LTR, also revealed a significant transcriptional contribution of upstream elements. The 19-bp TATA region from the MMTV LTR was shown to have considerably more activity in this transcription system than comparable TATA regions from other promoters. Sequences critical to the MMTV TATA region were evaluated by single base pair mutagenesis and found to comprise a consensus TATA box sequence, TATAAAA, as well as a single A just upstream of the TATAAAA sequence. Thus, the high level of basal transcription observed with the TATA region from MMTV is due to a perfect consensus TATA box sequence and a single base immediately 5' adjacent. It is likely that the high basal rate of transcription observed with this TATA box region on histone-free templates represents an inappropriate level of basal expression and that a complete evaluation of transactivation mechanisms in this system will require the recapitulation in vitro of the chromatin-mediated repressive state that exists in vivo. |
| Databáze: | OpenAIRE |
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