Nucleic acids symposium series (2004)最新文献

A variety of 2'-O-arylnucleosides with functional groups were synthesized by the microwave-assisted reaction of 2,2'-anhydrouridine with phenol derivatives. The 2'-O-arylnucleosides thus obtained were incorporated into 2'-O-Me RNA or DNA oligomers and their hybridization properties were studied by T(m) measurements.

Human apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) is known to play a role in intrinsic cellular immunity against human immunodeficiency virus type 1 (HIV-1). The antiretroviral activity of APOBEC3G is associated with hypermutation of viral DNA through cytidine deamination. APOBEC3G contains two cytidine deaminase domains that are characterized by a highly conserved zinc-coordinating motif. It is known that only the C-terminal domain of APOBEC3G (c-APOBEC3G) is involved in the catalytic activity. Here, we present the solution structure and the interaction with single-stranded DNA of c-APOBEC3G. Furthermore, we have succeeded for the first time in monitoring the deamination reaction of c-APOBEC3G in real-time using NMR signals. The monitoring has demonstrated that the deamination reaction occurs in a strict 3'-->5'

We describe a selective and sensitive single-nucleotide polymorphism (SNP) typing of genes from rice cultivars by using DNA photoligation. This SNP typing method facilitates qualitative determination of genes from indica and japonica rice, and showed a high degree of single nucleotide specificity.

Radiolytic one-electron reduction of oligodeoxynucleotides (ODNs) possessing a disulfide bond induced strand exchange reaction in a hypoxia selective manner. In this study, we attempted to apply this radiolytic reaction to stem-and-loop structured ODNs. Hypoxic X-irradiation to an aqueous solution of stem-and-loop structured ODNs produced a cyclized DNA in good yield via an intrastrand ligation reaction.

The endogenous mutagenic/carcinogenic 9- (4'-aminophenyl) -9H- pyrido [3,4-b] indole (aminophenylnorharman, APNH) is formed from norharman and aniline in the presence of cytochrome P-450s. The major APNH-DNA adduct has been reported to be 2'-deoxyguanosin-8-yl-aminophenylnorhaman (dG-C8-APNH). In addition, demonstrated formation of APNH-RNA adduct and conducted a structural analysis using various spectrometric approaches. The compound produced from guanosine (Guo) and N-acetoxy-APNH, an ultimate mutagenic form of APNH, was concluded to be guanosin-8-yl-APNH (Guo-C8-APNH) on the basis of various spectroscopic analysis. The same adduct was found in the livers of rats administered APNH. The total adduct levels of APNH-RNA were six times higher than total APNH-DNA adducts in the same rat liver samples.

8-Oxoguanine is the typical oxidative product, but 8-oxoguanine is further oxidized by several oxidizing agents. Here, we investigated the oxidation of 2'-deoxy-8-oxoguanosine with aqueous iodine.

Oligonucleotide that can reversibly alter the duplex-forming ability in response to an external factor has potential to be applied to various genome technologies, e.g. antisense and gene diagnosis technology. A novel bridged nucleoside which is capable of sensing an oxidant and reductant was designed and synthesized. The nucleoside formed a disulfide bridge between C2' and C4' positions, which would enhance its duplex-forming ability under oxidative conditions. Contrastingly, the disulfide bridge was cleaved under reductive conditions; it could cause decrease of duplex-forming ability.

TLS (Translocated in liposarcoma) has been characterized as a rearranged gene in chromosomal translocations specific of human myxoid liposarcoma. The various cellular functions of TLS participating either in transcription or splicing processes are thought the involvement of an interaction of TLS with DNA and/or RNA. To investigate insight into DNA-TLS interaction, we performed Electrophoretic mobility shift assay of TLS with G-quadruplex DNA. It revealed that TLS especially bound to single stranded human telomeric DNA in the presence of potassium ion while it was not able to bind double stranded human telomeric DNA and single stranded human telomeric DNA in the presence of sodium ion.

In order to study telomerase activation in normal cells, a telomerase-immortalized fibroblast cell line, hTERT-BJ1, treated with a telomerase inhibitor, 3'-azido-2',3'-dideoxyguanosine (AZddG), is considered to be a good model. Long-term treatment with AZddG resulted in telomere shortening from 10-20 kbp to 5-6 kbp in cultured hTERT BJ1 cells. However, the telomere length then stabilized. As expected, removal of AZddG from the culture medium induced telomere lengthening in the cells, suggesting that telomerase activity was recovered upon AZddG removal. The effect of recovery of telomerase activity in hTERT-BJ1 cells will be investigated in future studies.

Efficient methods for the modification of RNA molecules have been expected as innovative biological tools and therapeutic methods. In this study, the development of a general method for site-specific RNA modification by the functionality-transfer ODN probes has been investigated. Site-specific and cytosine-selective RNA modifications were achieved by the functionality-transfer reaction. It was shown that the base and site-selectivity were due to the close proximity of the reactants in the DNA-RNA duplexes.