Upstream activating sequence

About: Upstream activating sequence is a research topic. Over the lifetime, 1633 publications have been published within this topic receiving 100112 citations.

Alternative Promoters and Tissue-Specific Regulation of Mouse oct-1 Gene Transcription

Abstract: The gene encoding mouse transcription factor Oct-1 contains two exons, 1U and 1L, at the 5′ end. Oct-1 mRNA from all tissues contains exon 1U, whereas exon 1L is found only in Oct-1 mRNA from mouse and human lymphoid cells. Upstream of 1U and 1L exons, the respective specific promoters, U and L, are located at a considerable distance from each other (67 kb in the mouse otf-1 locus). These regions differ in their structure. The region upstream from exon 1U contains numerous Sp1 sites, whereas the region upstream from exon 1L contains homeospecific NTAATNN sites and two octa sites ATGCAAAT recognized by transcription factors Oct-1, Oct-2, and by other POU domain-containing proteins. The octa and homeospecific sites promote autoregulation of the oct-1 gene. Transfection of U and L promoter fragments within pGL3 Basic plasmid or pGL3 Enhancer vector into lymphoid NS/0 myeloma cells or 10(1) fibroblasts showed that the L promoter activity was many times higher in the myeloma cells than in fibroblasts. Between the sites of translation and transcription initiation from the L promoter, a nucleotide sequence was identified whose elimination resulted in a significantly higher efficiency of transcription initiation from this promoter. Thus, the oct-1 gene contains at least two alternative promoters: the U promoter apparently provides for the constitutive synthesis of Oct-1 protein, whereas the L promoter manifests tissue specificity, contains octa sites, and appears to be self-regulated.

Potential transcriptional regulatory regions exist upstream of the human ezrin gene promoter in esophageal carcinoma cells

Abstract: We previously demonstrated that the region -87/+134 of the human ezrin gene (VIL2) exhibited promoter activity in human esophageal carcinoma EC109 cells, and a further upstream region -1324/-890 positively regulated transcription. In this study, to identify the transcriptional regulatory regions upstream of the VIL2 promoter, we cloned VIL2 -1541/-706 segment containing the -1324/-890, and investigated its transcriptional regulatory properties via luciferase assays in transiently transfected cells. In EC109 cells, it was found that VIL2 -1541/-706 possessed promoter and enhancer activities. We also localized transcriptional regulatory regions by fusing 5'- or 3'-deletion segments of VIL2 -1541/-706 to a luciferase reporter. We found that there were three positive and one negative transcriptional regulatory regions within VIL2 -1541/-706 in EC109 cells. When these regions were separately located upstream of the luciferase gene without promoter, or located upstream of the VIL2 promoter or SV40 promoter directing the luciferase gene, only VIL2 -1297/-1186 exhibited considerable promoter and enhancer activities, which were lower than those of -1541/-706. In addition, transient expression of Sp1 increased ezrin expression and the transcriptional activation of VIL2 -1297/-1186. Other three regions, although exhibiting significantly positive or negative transcriptional regulation in deletion experiments, showed a weaker or absent regulation. These data suggested that more than one region upstream of the VIL2 promoter participated in VIL2 transcription, and the VIL2 -1297/-1186, probably as a key transcriptional regulatory region, regulated VIL2 transcription in company with other potential regulatory regions.

Multiple functional enhancer motifs of rat ribosomal gene

Abstract: Previous studies from this laboratory have characterized a 174 bp enhancer element which is located 2 kb upstream of the initiation site. Half of the enhancer action is controlled by a 37 bp element at the 3’ end of the 174 bp region. We now report that a 43 bp adjacent domain which is located upstream of the 37 bp element constitutes an additional motif of the rDNA enhancer. When the plasmid consisting of the 43 bp DNA upstream of the rDNA core promoter was transcribed in a fractionated rat tumor cell extract (fraction DE-B), transcription of rDNA was augmented 4 fold. Electrophoretic mobility shift and DNAase I footprinting analyses showed that the purified 37 bp enhancer (E1-binding protein, (E1BF) not only interacted with the enhancer motif E1 but also interacted with the neighbouring 43 bp enhancer domain E2. The specificity of the binding was demonstrated by competition with unlabeled 37 bp and 43 bp fragment and lack of competition with nonspecific DNAs in the mobility shift assay. These studies have shown that a single pol I transcription factor can bind to multiple enhancer domains with no significant sequence homologies and such multiple interactions may result in maximal transcription of ribosomal gene from the core promoter.

Transcription adaptors in eukaryotes

Abstract: The present invention relates to a protein or protein complex which stimulates activated DNA transcription in eukaryotic cells, genes encoding the protein or proteins, and uses therefor. The protein or protein complex, referred to herein as a transcriptional adaptor, is associated with two other factors, each of which, in turn, binds to a region of a eukaryotic promoter. The first of these factors, referred to herein as an activator, binds to a region of the promoter DNA sequence termed the UAS binding site or enhancer. The second factor or factors, referred to herein as a general transcription factor (GTF), binds to second region of the promoter DNA sequence, termed the TATA box, which is located downstream from the UAS binding site. The transcriptional adaptor specifically binds to an acidic activation domain (i.e., one which is highly enriched in acidic amino acids, such as aspartic acid and glutamic acid) on the activator protein which, in addition, includes a DNA binding domain.

Investigating Tissue- and Organ-specific Phytochrome Responses using FACS-assisted Cell-type Specific Expression Profiling in Arabidopsis thaliana

Abstract: Light mediates an array of developmental and adaptive processes throughout the life cycle of a plant. Plants utilize light-absorbing molecules called photoreceptors to sense and adapt to light. The red/far-red light-absorbing phytochrome photoreceptors have been studied extensively. Phytochromes exist as a family of proteins with distinct and overlapping functions in all higher plant systems in which they have been studied1. Phytochrome-mediated light responses, which range from seed germination through flowering and senescence, are often localized to specific plant tissues or organs2. Despite the discovery and elucidation of individual and redundant phytochrome functions through mutational analyses, conclusive reports on distinct sites of photoperception and the molecular mechanisms of localized pools of phytochromes that mediate spatial-specific phytochrome responses are limited. We designed experiments based on the hypotheses that specific sites of phytochrome photoperception regulate tissue- and organ-specific aspects of photomorphogenesis, and that localized phytochrome pools engage distinct subsets of downstream target genes in cell-to-cell signaling. We developed a biochemical approach to selectively reduce functional phytochromes in an organ- or tissue-specific manner within transgenic plants. Our studies are based on a bipartite enhancer-trap approach that results in transactivation of the expression of a gene under control of the Upstream Activation Sequence (UAS) element by the transcriptional activator GAL43. The biliverdin reductase (BVR) gene under the control of the UAS is silently maintained in the absence of GAL4 transactivation in the UAS-BVR parent4. Genetic crosses between a UAS-BVR transgenic line and a GAL4-GFP enhancer trap line result in specific expression of the BVR gene in cells marked by GFP expression4. BVR accumulation in Arabidopsis plants results in phytochrome chromophore deficiency in planta5-7. Thus, transgenic plants that we have produced exhibit GAL4-dependent activation of the BVR gene, resulting in the biochemical inactivation of phytochrome, as well as GAL4-dependent GFP expression. Photobiological and molecular genetic analyses of BVR transgenic lines are yielding insight into tissue- and organ-specific phytochrome-mediated responses that have been associated with corresponding sites of photoperception4, 7, 8. Fluorescence Activated Cell Sorting (FACS) of GFP-positive, enhancer-trap-induced BVR-expressing plant protoplasts coupled with cell-type-specific gene expression profiling through microarray analysis is being used to identify putative downstream target genes involved in mediating spatial-specific phytochrome responses. This research is expanding our understanding of sites of light perception, the mechanisms through which various tissues or organs cooperate in light-regulated plant growth and development, and advancing the molecular dissection of complex phytochrome-mediated cell-to-cell signaling cascades.