A CpG island promoter drives the CXXC5 gene expression

CXXC5 is a member of the zinc-finger CXXC family that binds to unmethylated CpG dinucleotides. CXXC5 modulates gene expressions resulting in diverse cellular events mediated by distinct signaling pathways. However, the mechanism responsible for CXXC5 expression remains largely unknown. We found here that of the 14 annotated CXXC5 transcripts with distinct 5 ' untranslated regions encoding the same protein, transcript variant 2 with the highest expression level among variants represents the main transcript in cell models. The DNA segment in and at the immediate 5 '-sequences of the first exon of variant 2 contains a core promoter within which multiple transcription start sites are present. Residing in a region with high G-C nucleotide content and CpG repeats, the core promoter is unmethylated, deficient in nucleosomes, and associated with active RNA polymerase-II. These findings suggest that a CpG island promoter drives CXXC5 expression. Promoter pull-down revealed the association of various transcription factors (TFs) and transcription co-regulatory proteins, as well as proteins involved in histone/chromatin, DNA, and RNA processing with the core promoter. Of the TFs, we verified that ELF1 and MAZ contribute to CXXC5 expression. Moreover, the first exon of variant 2 may contain a G-quadruplex forming region that could modulate CXXC5 expression

Molecular recognition of poly(A) by small ligands: an alternative method of analysis reveals nanomolar, cooperative and shape-selective binding

A few drug-like molecules have recently been found to bind poly(A) and induce a stable secondary structure (Tm ≈ 60°C), even though this RNA homopolymer is single-stranded in the absence of a ligand. Here, we report results from experiments specifically designed to explore the association of small molecules with poly(A). We demonstrate that coralyne, the first small molecule discovered to bind poly(dA), binds with unexpectedly high affinity (Ka >107 M−1), and that the crescent shape of coralyne appears necessary for poly(A) binding. We also show that the binding of similar ligands to poly(A) can be highly cooperative. For one particular ligand, at least six ligand molecules are required to stabilize the poly(A) self-structure at room temperature. This highly cooperative binding produces very sharp transitions between unstructured and structured poly(A) as a function of ligand concentration. Given the fact that junctions between Watson–Crick and A·A duplexes are tolerated, we propose that poly(A) sequence elements and appropriate ligands could be used to reversibly drive transitions in DNA and RNA-based molecular structures by simply diluting/concentrating a sample about the poly(A)-ligand ‘critical concentration’. The ligands described here may also find biological or medicinal applications, owing to the 3′-polyadenylation of mRNA in living cells

New aspects of the interaction of the antibiotic coralyne with RNA: coralyne induces triple helix formation in poly(rA)•poly(rU)

The interaction of coralyne with poly(A)•poly(U), poly(A)•2poly(U), poly(A) and poly(A)•poly(A) is analysed using spectrophotometric, spectrofluorometric, circular dichroism (CD), viscometric, stopped-flow and temperature-jump techniques. It is shown for the first time that coralyne induces disproportionation of poly(A)•poly(U) to triplex poly(A)•2poly(U) and single-stranded poly(A) under suitable values of the [dye]/[polymer] ratio (CD/CP). Kinetic, CD and spectrofluorometric experiments reveal that this process requires that coralyne (D) binds to duplex. The resulting complex (AUD) reacts with free duplex giving triplex (UAUD) and free poly(A); moreover, ligand exchange between duplex and triplex occurs. A reaction mechanism is proposed and the reaction parameters are evaluated. For CD/CP> 0.8 poly(A)•poly(U) does not disproportionate at 25°C and dye intercalation into AU to give AUD is the only observed process. Melting experiments as well show that coralyne induces the duplex disproportionation. Effects of temperature, ionic strength and ethanol content are investigated. One concludes that triplex formation requires coralyne be only partially intercalated into AUD. Under suitable concentration conditions, this feature favours the interaction of free AU with AUD to give the AUDAU intermediate which evolves into triplex UAUD and single-stranded poly(A). Duplex poly(A)•poly(A) undergoes aggregation as well, but only at much higher polymer concentrations compared to poly(A)•poly(U)

Small molecule recognition of homopurine nucleic acid structures

The thesis topic entitled above involves the use of small molecules as a general means to drive nucleic acid assembly and structural transitions. We have shown that coralyne, a crescent-shaped small molecule, can assemble homo-adenine DNA and RNA sequences into anti-parallel duplexes at neutral pH, a structure containing putative purine-purine (A*A) base pairs that is otherwise unstable. The importance of the structure of the small molecule in the recognition and stabilization of A*A base pairing has been established by experimental evidence. We further provide structural evidence for the putative A*A base pairing that is stabilized by coralyne and molecules of similar size and shape. Our hypothesis that planar molecules that are slightly too large to intercalate Watson-Crick base pairs might intercalate the larger purine-purine base pairs has led to the design of a new class of small molecules that tightly bind purine-purine duplexes with excellent selectively. We have demonstrated that azacyanines can exhibit strong and selective association with a human telomeric sequence that forms a unimolecular G-quadruplex in solution. The synthetic accessibility of azacyanines makes this class of molecules amenable to library preparation for high-throughput screening. Together, the findings reported in this thesis provide further evidence for the robust and versatile nature of selective small molecule recognition of nucleic acids, especially purine-purine duplexes.Ph.D.Committee Chair: Hud, Nicholas; Committee Member: Doyle, Donald; Committee Member: Lobachev, Kirill; Committee Member: Oyelere, Adegboyega; Committee Member: Wartell, Roge

Synthesis and characterization of mono- and dinuclear metal complexes with novel Azo compounds and their dyeing properties

The coupling reaction of 1-amino 4-(2' -amino benzene sulfonic acid) 2-methyl anthraquinone, 1-amino 4-(p-( -sulfatoetyl sulfonyl aniline) 2-methyl anthraquinone, 1-amino 4-(5' -amino naphtaline-3' -sulfonic acid) 2-methyl anthraquinone with 4-N-(4',6' -dichloro-s-triazine)- -sulfatoetyl sulfonic acid and 5-N-(4',6' -dichloro-s-triazine)naphtaline-2-sulfonic acid in the presence of sodium hydroxide solution were maintained to give anthraquinone derivatives after the diazotization reactions. The metal complexes of these ligands that have dye character were prepared with CrIII, CoIIand FeIII transition metal salts and their characterized by analytical and spectroscopic methods as mono and dinuclear complexes. Atomic absorption and magnetic susceptibility results showed that the complexes have octahedral geometry. The synthesized compounds were carried out for dyeing of cotton and wool fibers, which were observed the deeper colors according to their color space values. Their fastnesses such as washing, perspiration and light exhibited good qualities. Copyright © Taylor & Francis Group, LLC.TBAG 107T409Received 23 October 2009; accepted 11 November 2009. This research was supported by TUBITAK, TBAG 107T409, 2007. We thank the Department of Textile Engineering in Cukurova University for the color measurements. Address correspondence to: Emel Yildiz, Dept. of Chemistry, Arts, and Science Faculty, Cukurova University, Balcali, Adana, 01330, Turkiey. E-mail: [email protected]

Doping Agent Naphazoline Hydrochloride: Development of Simple and Fast Voltammetric Method for Its Determination in Human Serum

Electrochemical behavior of naphazoline hydrochloride on a carbon paste electrode that was modified with aluminium oxide nanoparticles (Al2O3NPs) was investigated in a Britton-Robinson (BR) buffer (pH 7.0) using various voltammetric techniques. The results support the presence of an irreversible and diffusion-controlled electrochemical oxidation signal of naphazoline hydrochloride which is approximately at 0.9 V vs. Ag/AgCl. A selective, accurate, and simple square-wave anodic adsorptive stripping voltammetric method was purposed for naphazoline hydrochloride detection. The linear response was within the range of 5.0 × 10-8- 3.0 × 10-5 mol L-1 with a detection limit of 2.6 × 10–8 mol L–1 (0.0064 mg L–1). In addition, the purposed method was also utilized for naphazoline hydrochloride determination in human serum sample

Correlations between ultrasonography findings and surgical findings in patients with refractory symptoms after primary surgical release for carpal tunnel syndrome

Objective: Surgical carpal tunnel release is very effective for symptom relief in carpal tunnel syndrome, and it remains the preferred choice of treatment. However, refractory symptoms following surgical release are not uncommon. We aimed to assess the usefulness of ultrasonography for determining the potential causes of ongoing symptoms following surgical release