Disease relevance of Dtl-dad

• Termination of RNA synthesis with 3'-O-Methylnucleoside 5'-triphosphates have been studied using E. coli RNA polymerase holoenzyme and poly [d(A-T)] as well as unfractionated T7 D delta III DNA as templates [1].
• Maximal transcription of DNA from a Halobacterium halobium phage øH (øH DNA) proceeds at pH 8.5 AND 75 DEGREES C. The enzyme is stable up to 75 degrees C and strictly requires a DNA template. øH DNA and poly[d(A-T) . d(A-T)] are the most efficient [2].
• Polymerase B could utilize poly d(A-T) and poly dAdT as templates, but could not use Bacillus cereus DNA though the structure is reported to be similar to that of poly d(A-T) [3].
• This susceptibility of d(A-T) sequences to 5,7-dimethoxycoumarin interaction has a corresponding influence on the survival of adenovirus because of the A-T-rich sequences that occur in some of the early gene regions of the adenovirus genome [4].

High impact information on Dtl-dad

• The transition enthalpy delta H for the B- to Z-DNA transition per mole base pairs (mbp) amounts to 2.0 +/- 0.2kcal for poly d(G-C), to 4.0 +/- 0.4kcal for poly d(A-T), and to 3.1 +/- 0.3kcal for poly d(A-C) poly d(G-T) [5].
• From the modification of the poly d(A-T) melting curve we estimate a maximum binding ratio of about one tetrameric repressor to about 20 basic pairs [6].
• We investigated the results of interactions of cisplatin, a DNA binding anticancer drug, and its inactive counterpart, transplatin isomer, on the molecular conformation of polynucleotides: poly d(G-C). poly d(G-C) (polyGC) and poly d(A-T). poly d(A-T) (polyAT) [7].
• The fidelity of poly [d(A-T)] copying catalyzed by DNA polymerase-beta-dissociated from liver chromatin was comparable to that of the chromatin-directed synthesis [8].
• In addition, there are distinct qualitative differences in the type of DNA present in the membrane fraction, with a more highly d(A-T) rich DNA being present in confluent (G0) cells than in cells during the S phase [9].

Chemical compound and disease context of Dtl-dad

• The order of binding for Nal and Oxo is: poly [d(G-C)] > poly [d(A- T)] > E. coli > poly (dG).(dC) > poly (dA).(dT) [10].
• The extent of these spectral effects depends strongly on the (A+T) content of the complexed DNA and decreased in the order: poly [d(A-T)], Clostridium perfringens DAN, Escherichia coli DNA, Micrococcus luteus DNA and poly(dC) [11].

Biological context of Dtl-dad

• Exposure of sulfhydryl groups as indicated by titration kinetics is decreased under conditions where RNA polymerase exists as a dimer or higher aggregate (low salt), in the presence of Mn2+, or when bound to d(A-T) [12].
• Poly [d(A-T)] melting studies suggest that at least three of the plasmid encoded SSBs are better helix-destabilizing proteins than is the E. coli SSB protein [13].
• Fluorescence energy transfer between dimethyldiazaperopyrenium dication and ethidium intercalated in poly d(A-T) [14].
• The enhancement phenomenon is sensitive to the base sequence of the polynucleotide with dye/poly r(A-U) and dye/poly r(G-C) combinations displaying enhanced antiviral activity, while dye/poly (rI).poly (rC) and dye/poly d(A-T) combinations do not [15].

Anatomical context of Dtl-dad

• In contrast to the situation in vivo, it is found that poly[d(A-T1 - d(A-T)] is as efficiently transcribed in vitro by oocyte polymerase as by egg polymerase [16].
• Additionally poly[d(A-T) - d(A-T)] is transcribed ten-fold more efficiently in vitro than calf thymus native DNA [16].
• The spectra reflected structural differences between poly[d(A-T).d(A-T)] and crab gonad DNA (which is extremely rich in d(A-T) base-pairing) [17].

Associations of Dtl-dad with other chemical compounds

• Competition experiments performed at various salt concentrations show that the stronger interaction of lac repressor for poly d(A-T) than for poly d(G-C) is based on difference in the dissociation rate of the complexes whereas the association rate for both polymers are similar [18].
• 1. When the synthetic polynucleotide, poly[d(A-T) - d(A-T)] is injected into the eggs and oocytes of Xenopus laevis, a stimulation of RNA synthesis results [16].
• FTIR study of netropsin binding to poly d(A-T) and poly dA.poly dT [19].
• We measured the fluorescence decay under polarized light, of ethidium bromide bound to the poly d(A-T) isolated from Cancer Pagurus [20].

Gene context of Dtl-dad

• Incubation of phenylmercurisulfonate with RNA polymerase above pH 9.0 results in loss of d(A-T) binding ability [12].
• It is shown that in 0.1 M phosphate buffer the CD measurement can be used to determine the binding constant of lac repressor to poly d(A-T) [18].
• The primer/template-independent polymerization appeared to proceed via two reactions, the slow process of formation of 16-19 nt long oligo d(A-T) without primer/template and the rapid process of elongation of the oligo d(A-T) by self-priming [21].
• delta Tth DNA polymerase catalyzed polymerization of dATP and dTTP into a high-molecular-weight d(A-T) copolymer using oligo-d(A-T) as the template/primer (Hanaki et al., Biochem. Biophys. Res. Commun. 244, 210-219) [22].
• But when the substrates were depleted, Taq DNA polymerase degraded the high molecular weigh d(A-T) polymer to the oligomers which were resistant to the further digestion by the 5'-->3' exonuclease activity of Taq DNA polymerase [21].

Analytical, diagnostic and therapeutic context of Dtl-dad

• In addition, the circular dichroism (C.D.) spectra of reconstituted chromatin with poly [d(A-T)] exhibits an increases intensity at about 262 nm [23].
• Z form of poly d(A-T).poly d(A-T) in solution studied by CD and UV spectroscopies [24].

References