SENSITIZED PHOTOINACTIVATION OF BACTERIOPHAGE <i>T</i>4

Meistrich, Marvin L.; Lamola, Angelo A.; Gabbay, Edmond J.

doi:10.1111/j.1751-1097.1970.tb05985.x

Cited by 29 publications

(11 citation statements)

References 18 publications

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“…Ac4D was synthesized according to Meistrich et al (5) from m-chloromethylacetophenone (6) and N,N-dimethyl-N'-acetylethylenediamine (7 Meistrich et al. (5) except for the peak at 4.726; instead they reported a peak at 2.246. Also, the melting point differs from the one they reported, 283-284TC.…”

Section: Methodsmentioning

confidence: 99%

Thymine dimer formation as a probe of the path of DNA in and between nucleosomes in intact chromatin.

Pehrson

1989

Proc. Natl. Acad. Sci. U.S.A.

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Photo-induced thymine dimer formation was used to probe nucleosome structure in nuclei. The distribution of thymine dimers in the nucleosome and recent studies of the structure of thymine dimer-containing DNA suggest that the rate of thymine dimer formation is affected by the direction and degree of DNA bending. This premise was used to construct a model of the path of DNA in the nucleosome, which has the following features. (i) There are four regions of sharp bending, two which have been seen previously by x-ray crystallography of the core particle. (i) The DNA in Hi-containing nucleosomes deviates from its superhelical path near the midpoint; this is not seen with Hl-stripped chromatin. (ii) The internucleosomal (linker) DNA appears to be relatively straight.Much of the knowledge about nucleosome structure comes from studies of isolated nucleosome core particles. Such studies provide only limited information about native chromatin structure since these particles lack histone H1, the internucleosomal (linker) DNA, and any constraints imposed by higher order chromatin structure. Therefore, it is valuable to develop methods to study nucleosome structure in situ. One such method is photodimerization of pyrimidines. Recently, the distribution of pyrimidine dimers (PDs) in core particles isolated from irradiated chromatin was described in careful detail (1, 2). Peaks of PD formation were found to occur with an average periodicity of 10.3 bases and were interpreted in terms of a footprint of histone-DNA interactions. Recent reports indicate that DNA in the immediate vicinity of a thymine dimer (TD) is bent toward the major groove (3, 4). Therefore, TDs should form preferentially wherever the DNA is already bent toward the major groove, and their distribution might reveal a great deal about the path of DNA in the nucleosome. Very little is known about the effect of H1 on the path of DNA in the nucleosome or about the path of DNA in the internucleosomal (linker) region. As this information is important for understanding higher order chromatin structure and the role of H1 in nucleosome structure, I have explored the possibility of using TD formation as an approach to gain such information. (5) except for the peak at 4.726; instead they reported a peak at 2.246. Also, the melting point differs from the one they reported, 283-284TC. However, the NMR spectrum and elemental analysis given here are consistent with the structure of AcOD, and the compound was found to be effective in greatly stimulating the production of TDs in DNA irradiated with light >310 nm. MATERIALS AND METHODSIsolation of Nuclei. All steps were carried out at 0-40C unless otherwise stated. Frozen rat livers (Pel-Freez Biologicals) were homogenized with a Waring blender in buffer A [0.34 M mannitol/60 mM KCl/15 mM NaCl/0.15 mM spermine/0.5 mM spermidine/2 mM EDTA/0.5 mM EGTA/15 mM triethanolamine/1% thiodiglycol/0.25 mM phenylmethanesulfonyl fluoride, pH 7.3] and filtered through cheese cloth, and nuclei were isolated essentially as described (8...

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Section: Methodsmentioning

confidence: 99%

Thymine dimer formation as a probe of the path of DNA in and between nucleosomes in intact chromatin.

Pehrson

1989

Proc. Natl. Acad. Sci. U.S.A.

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“…By the use of the triplet-state sensitizer, acetophenone, and near-UV light (> 300 nm), it is possible to populate exclusively the Thy triplet in DNA; ThyoThy(c,s) is the major product, along with small amounts (< 3%) of CytoThy, hThy, and Thy-acetophenone addition products (Lamola and Yamane, 1967;Meistrich et al, 1970). When acetone is used as a sensitizer, the Cyt triplet may also be excited, and some CytoCyt is formed (Ben Ishai et ah, 1968).…”

Section: Dimerization In Oligo-and Polynucleotidesmentioning

confidence: 99%

Pyrimidine Photodimers

Fisher¹,

Johns²

1976

Photochemistry and Photobiology of Nucleic Acids

117

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“…In the first place, it provides in principle a method to study the biological consequences of one type of photodamage in DNA to the exclusion of the many other types that are produced by direct absorption of energy in the far UV region by DNA bases. From results of studies on 254 nm and acetophenone-sensitized irradiation of phage T4, for example, Meistrich (1972) concluded that Thy < >Thy was a lethal lesion but not the only one, and that photoreactivation and u-gene repair act preferentially on Thy < >Thy but x-gene repair does not. Meistrich and Drake (1972) also showed that Thy< >Thy is a premutational lesion for both frameshift and G * C -+ A * T transition mutations in T4.…”

Section: Introductionmentioning

confidence: 99%

Studies on Thymine‐derived Uv Photo‐products in Dna—ii. A Comparative Analysis of Damage Caused by 254 Nm Irradiation and Triplet‐state Photosensitization

Patrick

Snow

1977

Photochem & Photobiology

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Abstract— From the rates of cyclobutyl dipyrimidine (Pyr < > Pyr) formation and the ratio of inactivation of transforming or phage DNA caused by direct (254 nm) or sensitized (1.0 M acetone, 313 nm; 0.02 M acetophenone, 334 nm) irradiation, we conclude that Thy < > Pyr and Cyt < > Pyr are equally lethal, and that they are repaired with equal efficiency by the host cell. Not all the damage formed by photosensitized irradlation can be photoenzymatically repaired, especially when acetone is the sensitizer. We found no compelling evidence for photosensitized interstrand cross‐links or sensitizer‐DNA addition products for the fluence range used in these studies (< 106 Jm‐2); moreover, strand breakage can account for only a part of the non‐photorepairable damage. We suggest that a fraction of the damage may be due to Pyr < > Pyr isomers other than the cis, syn type usually formed in native DNA by far‐UV light.

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SENSITIZED PHOTOINACTIVATION OF BACTERIOPHAGE T4

Cited by 29 publications

References 18 publications

Thymine dimer formation as a probe of the path of DNA in and between nucleosomes in intact chromatin.

Thymine dimer formation as a probe of the path of DNA in and between nucleosomes in intact chromatin.

Pyrimidine Photodimers

Studies on Thymine‐derived Uv Photo‐products in Dna—ii. A Comparative Analysis of Damage Caused by 254 Nm Irradiation and Triplet‐state Photosensitization

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