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.

A test of ‘polymerase handover’ as a mechanism for stimulating initiation by RNA polymerase I

Abstract: On the tandemly linked ribosomal genes of Xenopus laevis, the RNA polymerase transcribes past the 3' end of the 40S coding region and terminates at T3 just upstream of the gene promoter. The close proximity of T3 to the gene promoter, and the functional interdependence of these two elements, has led to the suggestion that polymerase terminating at T3 might be passed directly to the gene promoter. Such a mechanism might be necessary to maintain the characteristic high rate of transcription initiation seen on the ribosomal genes. We have performed a direct test of this model by introducing chain-terminating psoralen adducts into a circular plasmid containing a single gene promoter with its attendant T3 region upstream. We find that the psoralen adducts can completely prevent polymerase from traveling around the template circle (and thus prevent polymerase from approaching the promoter from upstream) without affecting the rate of transcription initiation at the gene promoter. This result suggests that recycling of polymerase from T3 to the promoter is not a significant mechanism in maintaining high initiation rates.

An n-Alkane-Responsive Promoter Element Found in the Gene Encoding the Peroxisomal Protein of Candida tropicalis Does Not Contain a C6 Zinc Cluster DNA-Binding Motif

Abstract: When an asporogenic diploid yeast, Candida tropicalis, is cultivated on n-alkane, the expression of the genes encoding enzymes of the peroxisomal β-oxidation pathway is highly induced. An upstream activation sequence (UAS) which can induce transcription in response to n-alkane (UASALK) was identified on the promoter region of the peroxisomal 3-ketoacyl coenzyme A (CoA) thiolase gene of C. tropicalis (CT-T3A). The 29-bp region (from −289 to −261) present upstream of the TATA sequence was sufficient to induce n-alkane-dependent expression of a reporter gene. Besides n-alkane, UASALK-dependent gene expression also occurred in the cells grown on oleic acid. Several kinds of mutant UASALK were constructed and tested for their UAS activity. It was clarified that the important nucleotides for UASALK activity were located within 10-bp region from −273 to −264 (5′-TCCTGCACAC-3′). This region did not contain a CGG triplet and therefore differed from the sequence of the oleate-response element (ORE), which is a UAS found on the promoter region of 3-ketoacyl-CoA thiolase gene of Saccharomyces cerevisiae. Similar sequences to UASALK were also found on several peroxisomal enzyme-encoding genes of C. tropicalis.

An essential gene in Saccharomyces cerevisiae shares an upstream regulatory element with PRP4

Abstract: ORF2 is an essential gene immediately upstream of PRP4 (formeryl RNA4), a gene involved in nuclear mRNA processing in Saccharomyces cerevisiae. The two genes are arranged head-to-head. An 8 base-pair conserved sequences element is found upstream of both genes, as well as upstream of certain other genes that are known to be involved in pre-mRNA processing. Through deletion analysis we have found that both of the conserved sequence elements are important for transcription of both genes. We have cloned ORF2 and have isolated temperature-sensitive orf2 mutants. The phenotype of these mutants does not suggest a role for ORF2 in mRNA processing. The deduced amino acid sequence of ORF2 indicates significant similarity to DPR1, a gene encoding a protein that is involved in the carboxy-terminal processing of G-protein.