scholarly journals Large-scale structural analysis of the core promoter in mammalian and plant genomes

2005 ◽  
Vol 33 (13) ◽  
pp. 4255-4264 ◽  
Author(s):  
K. Florquin
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Clemens Höflich ◽  
Angela Brieger ◽  
Stefan Zeuzem ◽  
Guido Plotz

AbstractPathogenic genetic variants in the ATP7B gene cause Wilson disease, a recessive disorder of copper metabolism showing a significant variability in clinical phenotype. Promoter mutations have been rarely reported, and controversial data exist on the site of transcription initiation (the core promoter). We quantitatively investigated transcription initiation and found it to be located in immediate proximity of the translational start. The effects human single-nucleotide alterations of conserved bases in the core promoter on transcriptional activity were moderate, explaining why clearly pathogenic mutations within the core promoter have not been reported. Furthermore, the core promoter contains two frequent polymorphisms (rs148013251 and rs2277448) that could contribute to phenotypical variability in Wilson disease patients with incompletely inactivating mutations. However, neither polymorphism significantly modulated ATP7B expression in vitro, nor were copper household parameters in healthy probands affected. In summary, the investigations allowed to determine the biologically relevant site of ATP7B transcription initiation and demonstrated that genetic variations in this site, although being the focus of transcriptional activity, do not contribute significantly to Wilson disease pathogenesis.


Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 94 ◽  
Author(s):  
Dario Fasino ◽  
Franca Rinaldi

The core–periphery structure is one of the key concepts in the structural analysis of complex networks. It consists of a partitioning of the node set of a given graph or network into two groups, called core and periphery, where the core nodes induce a well-connected subgraph and share connections with peripheral nodes, while the peripheral nodes are loosely connected to the core nodes and other peripheral nodes. We propose a polynomial-time algorithm to detect core–periphery structures in networks having a symmetric adjacency matrix. The core set is defined as the solution of a combinatorial optimization problem, which has a pleasant symmetry with respect to graph complementation. We provide a complete description of the optimal solutions to that problem and an exact and efficient algorithm to compute them. The proposed approach is extended to networks with loops and oriented edges. Numerical simulations are carried out on both synthetic and real-world networks to demonstrate the effectiveness and practicability of the proposed algorithm.


1992 ◽  
Vol 12 (3) ◽  
pp. 1352-1356 ◽  
Author(s):  
D C Leitman ◽  
E R Mackow ◽  
T Williams ◽  
J D Baxter ◽  
B L West

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.


2001 ◽  
Vol 276 (32) ◽  
pp. 30542-30551 ◽  
Author(s):  
Anna-Klara Rundlöf ◽  
Mattias Carlsten ◽  
Elias S. J. Arnér

1990 ◽  
Vol 10 (10) ◽  
pp. 5177-5186
Author(s):  
J Zhang ◽  
S T Jacob

Previous studies in our laboratory have characterized a 174-base-pair (bp) enhancer sequence in the rat ribosomal DNA spacer region that exhibits all of the characteristics of a polymerase (Pol) II enhancer. Further studies showed that at least half of the enhancer activity resides in a 37-bp motif (E1) within the 174-bp spacer sequence that is located between positions -2.183 and -2.219 kilobase pairs upstream of the initiation site. To identify the factor(s) that binds specifically to the 37-bp enhancer domain, we fractionated whole-cell extract from rat adenocarcinoma ascites cells by chromatography on a series of columns, including an oligodeoxynucleotide affinity column. The final preparation contained two polypeptides of molecular weights 79,400 and 89,100 and was completely devoid of RNA Pol I activity. Electrophoretic mobility shift analysis showed that the polypeptides in the purified preparation (designated E1BF) interacted with both the enhancer element and the core promoter. To determine whether each polypeptide can separately bind to the core promoter and the enhancer, the individual components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, renatured, and subjected to gel retardation analysis. This experiment demonstrated that both polypeptides interacted with the two cis-acting sequences. The specificity of the binding was demonstrated by competition with unlabeled 37-bp and core promoter fragments and lack of competition with nonspecific DNAs in the mobility shift assay. The 37-bp enhancer as well as the downstream sequence of the core promoter were protected by E1BF in the DNase I footprinting assay. Addition of E1BF to limiting amounts of fraction DE-B, which contains all factors essential for Pol I-directed transcription, resulted in three- to fourfold stimulation of ribosomal DNA transcription. Comparison of molecular weights and footprinting profiles did not reveal any relationship between E1BF and other Pol I trans-acting factors.


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