Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of somatostatin hormones are mediated by a family of five different seven-helix transmembrane spanning receptors (SSTR1-5). The expression of the five different SSTR subtypes displays a complex temporal- and tissue-specific pattern. To investigate the molecular mechanisms controlling the different expression patterns of the SSTRs, we cloned the 5'-flanking region of the human SSTR2 gene. Characterization of the SSTR2 promoter resulted in the identification of a novel initiator element (SSTR2inr). Transcriptional activity of the SSTR2inr is dependent on the presence of a binding site (E-box) for basic helix-loop-helix (bHLH) transcription factors. By screening a mouse brain cDNA expression library we isolated a cDNA coding for the bHLH transcription factor SEF-2. SEF-2 binds to the E-box present in the SSTR2inr, both in vitro and in vivo and activates transcription from the SSTR2inr. A single point mutation within the E-box eliminates binding of SEF-2 and results in a complete loss of transcriptional activity of the SSTR2inr. Furthermore, DNA binding studies demonstrate that the basal transcription factor TFIIB can be tethered to the SSTR2inr through physical interaction with SEF-2. In summary, the SSTR2inr represents a novel type of initiator element that confers gene expression in the absence of a TATA-box or binding sites for other known initiator factors, like YY-1 or USF.
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PMID:The helix-loop-helix transcription factor SEF-2 regulates the activity of a novel initiator element in the promoter of the human somatostatin receptor II gene. 897 94

Somatostatin (SRIF) exerts inhibitory effects on virtually all endocrine and exocrine secretions. At least five distinct human SRIF receptors have been identified ( SST1-SST5). Analysis of the promoter region may provide tools to understand transcriptional regulation of SSTS in various tissues, indicating specific functions. Transcriptional regulation of the human SST1 was analyzed in the present study. Total RNA from a human somatotropic pituitary tumor was reverse transcribed. 5'cDNA regions of the human SST1 were cloned using an adapted inverse PCR method. Among the 15 PCR clones analyzed, 9 demonstrated an extended 5'-utr of 266 nucleotides, determining a thymidine residue as a major transcription start site. No introns were evident in the 5'-utr region. The promoter region lacked consensus sites for TATA or CAAT boxes, YY1, or an initiator sequence, but contained two CpG islands. Different lengths of 5'-flanking regions cloned by PCR were placed upstream of the luciferase reporter gene and transiently transfected into various cell lines. The 2834 nt of the promoter region directed significant transcriptional activity in a somatotropic pituitary cell line, but neither in COS-7 monkey kidney cells nor in AtT-20 murine corticotrope cells. Transcriptional activity was not affected by incubation with various hormones. Several putative transcription factor binding sites inducing the cell-type specific activity were identified.
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PMID:Characterization and transcriptional regulation of the human somatostatin receptor subtype 1 gene. 1753 78

Neuroendocrine cancer cell lines are used to investigate therapeutic targets in neuroendocrine tumors (NET) and have been instrumental in the design of clinical trials targeting the PI3K/AKT/mTOR pathways, VEGF inhibitors, and somatostatin analogues. It remains unknown, however, whether the genomic makeup of NET cell lines reflect that of primary NET since comprehensive unbiased genome sequencing has not been performed on the cell lines. Four bronchopulmonary NET (BP-NET)-NCI-H720, NCI-H727, NCI-H835, and UMC11-and two pancreatic neuroendocrine tumors (panNET)-BON-1 and QGP1-were cultured. DNA was isolated, and exome sequencing was done. GATK and EXCAVATOR were used for bioinformatic analysis. We detected a total of 1,764 nonsynonymous single nucleotide variants at a rate of 8 per Mb in BP-NET and 4.3 per Mb in panNET cell lines, including 52 mutated COSMIC cancer genes in these cell lines, such as TP53, BRCA1, RB1, TSC2, NOTCH1, EP300, GNAS, KDR, STK11, and APC but not ATRX, DAXX, nor MEN1. Our data suggest that mutation rate, the pattern of copy number variations, and the mutational spectra in the BP-NET cell lines are more similar to the changes observed in small cell lung cancer than those found in primary BP-NET. Likewise, mutation rate and pattern including the absence of mutations in ATRX/DAXX, MEN1, and YY1 in the panNET cell lines BON1 and QGP1 suggest that these cell lines do not have the genetic signatures of a primary panNET. These results suggest that results from experiments with BP-NET and panNET cell lines need to be interpreted with caution.
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PMID:Exome-level comparison of primary well-differentiated neuroendocrine tumors and their cell lines. 2634 99