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51.
High mobility group A1 (HMGA1), a non-histone chromosomal protein, is highly expressed in a wide range of human cancers including cervical, breast, and prostate cancers. Therefore, hmga1 gene is considered as an attractive potential target for anticancer drugs. We have chosen 27 bp DNA sequence from a regulatory region of hmga1 promoter and studied its interaction with adriamycin (ADM) and in vitro expression of HMGA1 in the presence of ADM in HeLa cell line. A variety of biophysical techniques were employed to understand the characteristics of [DNA–ADM] complex. Spectrophotometric titration data, DNA denaturation profiles, and quenching of fluorescence of ADM in the presence of DNA demonstrated a strong complexation between DNA and ADM with a high binding affinity (Ka) of 1.3 × 106 M?1 and a stoichiometry of 1:3 (drug:nucleotide). The energetics of binding obtained from isothermal titration calorimetry and differential scanning calorimetry suggest the binding to be exothermic and enthalpy (?H, ?6.7 ± 2.4 kcal M?1) and entropy (TΔS, 18.5 ± 6.4 kcal M?1) driven (20°C), which is typical of intercalative mode of binding. Further, results on decreased expression (by ~70%) of HMGA1 both at mRNA and protein levels in association with the observed cell death (by ~75%) in HeLa cell line, clearly confirm that ADM does target hmga1; however, the effect of ADM on genes other than hmga1 either directly or via hmga1-mediated pathways cannot be ruled out in the observed cytotoxicity. Therefore, hmga1 in general and particularly the regulatory region is a promising target for therapeutic strategy in combating cancer. 相似文献
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Mohammad Nazim Uddin Patrice Dunoyer Gregory Schott Salina Akhter Chunlin Shi William J. Lucas Olivier Voinnet Jae-Yean Kim 《Nucleic acids research》2014,42(12):7971-7980
RNA silencing is an evolutionarily conserved mechanism triggered by double-stranded RNA that is processed into 21- to 24-nt small interfering (si)RNA or micro (mi)RNA by RNaseIII-like enzymes called Dicers. Gene regulations by RNA silencing have fundamental implications in a large number of biological processes that include antiviral defense, maintenance of genome integrity and the orchestration of cell fates. Although most generic or core components of the various plant small RNA pathways have been likely identified over the past 15 years, factors involved in RNAi regulation through post-translational modifications are just starting to emerge, mostly through forward genetic studies. A genetic screen designed to identify factors required for RNAi in Arabidopsis identified the serine/threonine protein kinase, TOUSLED (TSL). Mutations in TSL affect exogenous and virus-derived siRNA activity in a manner dependent upon its kinase activity. By contrast, despite their pleiotropic developmental phenotype, tsl mutants show no defect in biogenesis or activity of miRNA or endogenous trans-acting siRNA. These data suggest a possible role for TSL phosphorylation in the specific regulation of exogenous and antiviral RNA silencing in Arabidopsis and identify TSL as an intrinsic regulator of RNA interference. 相似文献
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Donner PL Xie Q Pratt JK Maring CJ Kati W Jiang W Liu Y Koev G Masse S Montgomery D Molla A Kempf DJ 《Bioorganic & medicinal chemistry letters》2008,18(8):2735-2738
In our program to discover non-nucleoside, small molecule inhibitors of genotype 1 HCV polymerase, we investigated a series of promising analogs based on a benzothiadiazine screening hit that contains an ABCD ring system. After demonstrating that a methylsulfonylamino D-ring substituent increased the enzyme potency into the low nanomolar range, we explored a minimum core required for activity by truncating to a three-ring system. Described herein are the syntheses and structure-activity relationship of a set of inhibitors lacking the A-ring of an ABCD ring system. We observed that small aromatic rings and alkenyl groups appended to the 5-position of the B-ring were optimal, resulting in inhibitors with low nanomolar potencies. 相似文献
57.
Peroxynitrite and NO donors form colored nitrite adducts with sinapinic acid: potential applications
Shirin Akhter James R. Green Paul Root Gregory J. Thatcher Bulent Mutus 《Nitric oxide》2003,8(4):214-221
Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid, SA) reacted with peroxynitrous acid at neutral pH with a second-order rate constant of 812 M(-1)s(-1), to yield a red product (lambda(max), 532 nm). The identical colored product could be formed with acidified decomposed peroxynitrous acid solutions or nitrite at slower rates (0.1M HCl, 8.32 M(-1)s(-1); 10% acetic acid, 0.0004 M(-1)s(-1)). The red compound is thought to be O-nitrososinapinic acid (3,5-dimethoxy-4-nitrosooxycinnamic acid) which can be formed by reaction with either peroxynitrous acid or nitrous acid. The extinction coefficient of O-nitrososinapinic acid (ONSA) was estimated to be 8419 M(-1)cm(-1) at 510 nm in 10% acetic acid and 90% acetonitrile. ONSA was also formed via NO(+) transfer from S-nitrosoglutathione (GSNO). ONSA in turn can S-nitrosate low molecular weight thiols and protein thiols. SA was also shown to act as a peroxynitrite sink as it effectively prevented the oxidation of dihydrorhodamine under physiological conditions. The fact that O-nitrososinapinic acid is stable and can be used to S-nitrosate thiol containing amino acids, peptides, and proteins makes it a potentially useful reagent in the study of S-nitrosothiol biochemistry and physiology. In addition, the relatively high extinction coefficient of O-nitrososinapinic acid means that it could be utilized as an analyte for the spectroscopic detection of peroxynitrite or NO(+)-donors in the submicromolar range. 相似文献
58.
E Shoeb U Badar J Akhter H Shams M Sultana MA Ansari 《World journal of microbiology & biotechnology》2012,28(3):1021-1025
The horizontal gene transfer of plasmid-determined stress tolerance was achieved under lab conditions. Bacterial isolates,
Enterobacter cloacae (DGE50) and Escherichia coli (DGE57) were used throughout the study. Samples were collected from contaminated marine water and soil to isolate bacterial
strains having tolerance against heavy metals and antimicrobial agents. We have demonstrated plasmid transfer, from Amp+Cu+Zn− strain (DGE50) to Amp−Cu−Zn+ strain (DGE57), producing Amp+Cu+Zn+ transconjugants (DGETC50→57) and Amp+Cu−Zn+ transformants (DGETF50→57). DGE57 did not carry any plasmid, therefore, it can be speculated that zinc tolerance gene in DGE57 is located on chromosome.
DGE50 was found to carry three plasmids, out of which two were transferred through conjugation into DGE57, and only one was
transferred through transformation. Plasmid transferred through transformation was one out of the two transferred through
conjugation. Through the results of transformation it was revealed that the genes of copper and ampicillin tolerance in DGE50
were located on separate plasmids, since only ampicillin tolerance genes were transferred through transformation as a result
of one plasmid transfer. By showing transfer of plasmids under lab conditions and monitoring retention of respective phenotype
via conjugation and transformation, it is very well demonstrated how multiple stress tolerant strains are generated in nature. 相似文献
59.
Akhter SA D'Souza KM Petrashevskaya NN Mialet-Perez J Liggett SB 《American journal of physiology. Heart and circulatory physiology》2006,290(4):H1427-H1432
Association studies suggest beta(1)-adrenergic receptor (beta(1)-AR) polymorphisms are disease modifiers in heart failure. The Arg389 variant has increased coupling to G(s) in transfected cells and evokes enhanced ventricular function in transgenic mice. Here, we assessed the differential effects of the human Gly389 and Arg389 beta(1)-AR polymorphisms on myocardial recovery after ischemic injury. Function was studied in transgenic mice with cardiac-specific expression of either human Gly389 or Arg389 beta(1)-AR at baseline and after 20 min of ex vivo ischemia and reperfusion (I/R). In 3-mo-old mice of either genotype, there was poor recovery after I/R (approximately 38% vs. approximately 68% for nontransgenic). Paradoxically, at 6 mo of age, functional recovery remained severely depressed in Gly389 hearts (approximately 32%) but was similar to nontransgenic for Arg389 hearts (approximately 60%). In Arg389 hearts, agonist-promoted adenylyl cyclase activities were depressed by approximately 35% at 6 mo of age, and G protein-coupled receptor kinase (GRK) activity was increased by approximately twofold compared with Gly389. Furthermore, I/R evoked an approximately threefold increase in ERK2 phosphorylation in Arg389 but an approximately twofold decrease in Gly389 hearts. Individually, these changes have been shown to mitigate I/R injury; thus the Arg389-beta(1)-AR uniquely evokes specialized pathways that act to protect against I/R injury. The improved recovery of function after I/R in Arg389 hearts relative to Gly389 appears to be due to an adaptive multimechanism program with allele-specific alterations in receptor signaling, GRK activity, and ERK2. Thus genetic variation of the human beta(1)-AR may play a role in cardiac functional recovery after ischemic injury. 相似文献
60.
Terry Disz Sajia Akhter Daniel Cuevas Robert Olson Ross Overbeek Veronika Vonstein Rick Stevens Robert A Edwards 《BMC bioinformatics》2010,11(1):319