| Popis: |
The human adenovirus E2-early promoter has a complex architecture consisting of overlapping sequences that constitute the major(+1) and minor(-26) promoters in human cells. In human cells the basal transcription of the major promoter is dependent on 4 cis-acting elements: a TTAAGA motif analogous to the TATA box, two E2F sites that are present as inverted repeats, and an ATF/CREB site. It was also demonstrated that the E2-early promoter was expressed efficiently in the fission yeast Schizosaccharomyces pombe and that the major and minor promoters were differentially utilized with preferential transcription from the -26 promoter. In this report the results of an investigation of the E2-early promoter activity in S. pombe, using an additional group of linkerscan mutants that span the E2 promoter, are presented. The efficient expression of the E2-early promoter in yeast was dependent on all 4 cis-acting elements as monitored by reporter gene expression. However, unlike the situation in human cells, the mutation of the TATA-like element present at -50 bps rendered the -26 promoter inactive and was therefore crucial for the maximal promoter function in S. pombe. As in human cells the wild type promoter activity was seen in S. pombe when the -82 to -92 region was mutated. DNA-protein interaction studies confirmed the presence of ATF and E2F-like transcription factor activities in S. pombe. This report demonstrates the degree of conservation that exists between the transcription apparatus of yeast and man. |
