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.

Elements of an archaeal promoter defined by mutational analysis

Abstract: The sequence requirements for specific and efficient transcription from the 16S/23S rRNA promoter of Sulfolobus shibatae were analysed by point mutations and by cassette mutations using an in vitro transcription system. The examination of the box A-containing distal promoter element (DPE) showed the great importance of the TA sequence in the center of box A for transcription efficiency and the influence of the sequence upstream of box A on determining the distance between the DPE and the start site. In most positions of box A, replacement of the wild type bases by adenines or thymines are less detrimental than replacements by cytosines or guanines. The effectiveness of the proximal promoter element (PPE) was not merely determined by its high A + T content but appeared to be directly related to its nucleotide sequence. At the start site a pyrimidine/purine (py/pu) sequence was necessary for unambiguous initiation as shown by analysis of mutants where the wild type start base was replaced. The sequence of box A optimal for promoter function in vitro is identical to the consensus of 84 mapped archaeal promoter sequences.

Spatial and Temporal Control of Gene Expression in Drosophila Using the Inducible GeneSwitch GAL4 System. I. Screen for Larval Nervous System Drivers

Abstract: There is a critical need for genetic methods for the inducible expression of transgenes in specific cells during development. A promising approach for this is the GeneSwitch GAL4 system of Drosophila. With GeneSwitch GAL4 the expression of upstream activating sequence (UAS) effector lines is controlled by a chimeric GAL4 protein that becomes active in the presence of the steroid RU486 (mifepristone). To improve the utility of this expression system, we performed a large-scale enhancer-trap screen for insertions that yielded nervous system expression. A total of 204 GeneSwitch GAL4 lines with various larval expression patterns in neurons, glia, and/or muscle fibers were identified for chromosomes I–III. All of the retained lines show increased activity when induced with RU486. Many of the lines reveal novel patterns of sensory neurons, interneurons, and glia. There were some tissue-specific differences in background expression, with muscles and glia being more likely to show activity in the absence of the inducing agent. However, >90% of the neuron-specific driver lines showed little or no background activity, making them particularly useful for inducible expression studies.

Efficient expression of the Saccharomyces cerevisiae PGK gene depends on an upstream activation sequence but does not require TATA sequences.

Abstract: The Saccharomyces cerevisiae PGK (phosphoglycerate kinase) gene encodes one of the most abundant mRNA and protein species in the cell. To identify the promoter sequences required for the efficient expression of PGK, we undertook a detailed internal deletion analysis of the 5' noncoding region of the gene. Our analysis revealed that PGK has an upstream activation sequence (UASPGK) located between 402 and 479 nucleotides upstream from the initiating ATG sequence which is required for full transcriptional activity. Deletion of this sequence caused a marked reduction in the levels of PGK transcription. We showed that PGK has no requirement for TATA sequences; deletion of one or both potential TATA sequences had no effect on either the levels of PGK expression or the accuracy of transcription initiation. We also showed that the UASPGK functions as efficiently when in the inverted orientation and that it can enhance transcription when placed upstream of a TRP1-IFN fusion gene comprising the promoter of TRP1 fused to the coding region of human interferon alpha-2.

NifA-dependent in vivo protection demonstrates that the upstream activator sequence of nif promoters is a protein binding site.

Abstract: Primer-extension analysis of the Klebsiella pneumoniae nifH promoter was used to determine changes in the accessibility of the promoter DNA to methylation after exposure of growing cells to dimethyl sulfate. Four guanine residues present in the nifH upstream activator sequence (UAS), the proposed NifA binding site, were protected from methylation and two guanine residues were hypermethylated when the transcriptional activator protein NifA was present in the cells. The interaction detected at the nifH UAS was independent of the alternative sigma factor NtrA required for transcription of the nifH and other nif promoters. Mutations within the nifH UAS that diminish NifA-dependent transcriptional activation reduced the interaction at the UAS. It seems likely that the pattern of methylation protection observed in the nifH UAS is the result of NifA binding.