Determinants of rat albumin promoter tissue specificity analyzed by an improved transient expression system.
AUTOR(ES)
Heard, J M
RESUMO
The 150-base-pairs region located upstream of the transcriptional start site of the rat albumin gene contains all of the critical sequences necessary for this gene's tissue-specific expression in rat hepatoma cells. In transient expression assays using an improved CAT system or direct mRNA analysis we were able to detect a faithful transcription from the albumin promoter in albumin-negative dedifferentiated H5 hepatoma cells which was 250-fold weaker than in differentiated H4II hepatoma cells producing albumin. This strong tissue specificity could be completely overcome through the cis action of a non-tissue-specific enhancer. Two upstream regions from nucleotides -151 to -119 and from -118 to -94, were required for efficient transcription in H4II cells. Each region contained a sequence motif highly conserved among different species. The effect of the -151/-119 region was strictly tissue specific, while the -118/-94 region was also involved in the low level of transcription observed in H5 cells. Finally, sequences between the CCAAT box and the TATA box also contributed to the overall tissue specificity of rat albumin gene transcription.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=365374Documentos Relacionados
- Astrovirus ribosomal frameshifting in an infection-transfection transient expression system.
- Application of an improved intracardiac fibreoptic system.
- The rat albumin gene promoter is appropriately regulated in transient but not in stable transfections.
- Deletion analysis of a phytochrome-regulated monocot rbcS promoter in a transient assay system.
- Characterization of middle T antigen expressed by using an adenovirus expression system.