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.

TATA-driven transcriptional initiation and regulation of the rat serotonin 5-HT1A receptor gene.

Abstract: The transcriptional initiation and regulation of the rat serotonin 5-HT1A receptor gene were characterized. By three types of analyses, a single brain-specific site of transcriptional initiation was localized to -967 bp upstream of the translation initiation codon that is utilized both in hippocampus and in the rat raphe RN46A cell line. This major site of transcriptional initiation was located 58 bp downstream from a consensus TATA element, suggesting TATA-driven transcription of the rat 5-HT1A receptor. To identify the promoter activity of the receptor gene, progressive 5' deletions of the -2,719/-117-bp fragment of the 5-HT1A promoter linked to luciferase gene were transfected into 5-HT1A-negative (pituitary GH4C1, L6 myoblast, and C6 glioma) and 5-HT1A-positive (septal SN-48 and raphe RN46A) cell lines. Enhancer regions were identified within a fragment between nucleotides -426 and -117 that selectively enhanced transcription in 5-HT1A-positive cells. A nonselective enhancer/promoter that mediated expression in all cell lines was located upstream between -1,519 and -426 bp in a DNA segment containing consensus TATA, CCAAT, SP-1, and AP-1 elements as well as a poly-GT26 dinucleotide repeat. Strong repression of transcription in all cell lines was conferred by the region upstream of -1,519 bp that contains a 152-bp DNA segment with >80% identity to RANTES, tumor necrosis factor-beta, and other immune system genes. Our results indicate that TATA-driven expression of the 5-HT1A receptor is regulated by a novel proximal tissue-specific enhancer region, a nonselective promoter, and an upstream repressor region that is distinct from previously identified neuron-specific repressors.

5′ upstream sequences of MyD88, an IL-6 primary response gene in M1 cells: detection of functional IRF-1 and Stat factors binding sites

Abstract: Transcription regulatory elements have been analyzed in upstream sequences of an Interleukin-6 (Il-6) primary response gene, MyD88. MyD88 2.3 kb mRNA is strongly and persistently induced in the course of myeloleukemic M1 cells differentiation with Il-6. MyD88 cDNA sequences were found in a region of 12 kb of mouse genomic DNA. Using Il-6 treated M1 cell RNAs, two transcription start sites have been localized, approximately 100 bp upstream from the 5' end of the cloned cDNA. We sequenced 1.4 kb of 5' genomic DNA including the first exon. In 5' of mRNA transcription start site, MyD88 nucleotidic sequence is 85% identical to 5' complementary sequences of the rat 3'-ketoacetyl CoA thiolase gene, over 1.2 kb. A DNA element conferring Il-6-inducible transcription to reporter genes, and localized 30 bp upstream of MyD88 first RNA start site, contains overlapping binding sites for cytokine activated transcription factors Stat and for the Interferon Regulatory Factor-1 and -2 (IRF-1 and IRF-2). In vitro binding assays showed that attachment of Stat factors to this element early in Il-6 treatment requires tyrosine kinase activation. IRF1, an activator of transcription, is also induced to bind to this sequence at later times. A model of persistent activation of MyD88 gene through these two types of factors is proposed.

The core promoter region of the tumor necrosis factor alpha gene confers phorbol ester responsiveness to upstream transcriptional activators.

Abstract: Activators of protein kinase C, such as 12-O-tetradecanoylphorbol 13-acetate (TPA), are known to regulate the expression of many genes, including the tumor necrosis factor alpha (TNF) gene, by affecting the level or activity of upstream transcription factors. To investigate the mechanism whereby TPA activates the TNF promoter, a series of 5'-deletion mutants of the human TNF promoter linked to chloramphenicol acetyltransferase was transfected into U937 human promonocytic cells. TPA produced a 7- to 11-fold activation of all TNF promoters tested, even those promoters truncated to contain only the core promoter with no upstream enhancer elements. The proximal TNF promoter containing only 28 nucleotides upstream and 10 nucleotides downstream of the RNA start site confers TPA activation to a variety of unrelated upstream enhancer elements and transcription factors, including Sp1, CTF/NF1, cyclic AMP-response element, GAL-E1a, and GAL-VP16. The level of activation by TPA depends on the TATA box structure, since the TPA response is greater in promoters containing the sequence TATAAA than in those containing TATTAA or TATTTA. These findings suggest that the core promoter region is a target for gene regulation by second-messenger pathways.

Identification of an upstream promoter of the human somatostatin receptor, hSSTR2, which is controlled by epigenetic modifications

Abstract: Somatostatin is a neuropeptide that inhibits exocrine and endocrine secretions of several hormones and negatively regulates cell proliferation. These events are mediated through somatostatin engagement on one of five G protein-coupled receptors named SSTR1 to STTR5. Somatostatin binding to SSTR2 mediates predominantly antisecretory and antiproliferative effects; two important biological activities in the gastroenteropancreatic endocrine and exocrine system. Herein we demonstrate novel regulatory sequences for human (h) SSTR2 transcription. By genomic DNA sequence analysis, we reveal two CpG islands located 3.8 kb upstream from the transcription start site. We identify a novel transcription start site and a promoter region within one of these CpG islands. We demonstrate that two epigenetic modifications, DNA methylation and histone acetylation, regulate the activation of hSSTR2 upstream promoter. Furthermore, we show that the transcription from this upstream promoter region directly correlates to hSSTR2 mRNA expression in various human cell lines. A combined treatment of a demethylating agent, 5-aza-2-deoxycytidine and a histone deacetylase inhibitor, trichostatin A, leads to increased expression of hSSTR2 mRNA in cell lines in which the CpG island is methylated. The epigenetic regulation of this promoter region results in differential expression of hSSTR2 mRNA in human cell lines. This study reveals the existence of a novel upstream promoter for the hSSTR2 gene that is regulated by epigenetic modifications, suggesting for complex control of the hSSTR2 transcription.