The fundamental objective of this research is a quantitative understanding of the stability of the DNA-histone core interaction in the nucleosome. This will be analyzed by studies of (a) the kinetics of nucleosome sliding on DNA, and (b) the dissociation equilibria of nucleosomes. Dissociation equilibria will be interpreted in terms of a model which includes the dissociation of the histone octamer into hexamers, tetramers and dimers of the histones. Sedimentation equilibrium will be used to analyze the histone core dissociation, and a combination of sedimentation equilibrium, sedimentation velocity and gel electrophoresis will be employed for the nucleosome dissociation studies. The effects of histone acetylation will be assayed, using reconstituted particles enriched in modified histones. The sliding process will be analyzed in two ways. Direct measurement of sliding of a histone core reconstituted in a phased fashion on a cloned DNA fragment will be used to determine the fundamental mechanism and basic sliding rate. The kinetics of nucleosome dissociation (which seems to involve a sliding mechanism) will be studied using circular dichroism and/or a new electrophoretic technique. Again, the influence of histone modification on the rate will be studied. There is evidence that stability of nucleosomes and their displacement on DNA may be of major importance in such processes as DNA replication, repair and transcription. Therefore, a quantitative analysis of DNA-histone interactions may be vital to a full comprehension of these processes on eukaryots.

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National Institute of General Medical Sciences (NIGMS)
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Molecular Biology Study Section (MBY)
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Oregon State University
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Robert, C H (1995) Estimating friction coefficients of mixed globular/chain molecules, such as protein/DNA complexes. Biophys J 69:840-8
Varga-Weisz, P; Zlatanova, J; Leuba, S H et al. (1994) Binding of histones H1 and H5 and their globular domains to four-way junction DNA. Proc Natl Acad Sci U S A 91:3525-9
Leuba, S H; Zlatanova, J; van Holde, K (1994) On the location of linker DNA in the chromatin fiber. Studies with immobilized and soluble micrococcal nuclease. J Mol Biol 235:871-80
Miloshev, G; Venkov, P; van Holde, K et al. (1994) Low levels of exogenous histone H1 in yeast cause cell death. Proc Natl Acad Sci U S A 91:11567-70
Varga-Weisz, P; van Holde, K; Zlatanova, J (1994) Competition between linker histones and HMG1 for binding to four-way junction DNA: implications for transcription. Biochem Biophys Res Commun 203:1904-11
Leuba, S H; Yang, G; Robert, C et al. (1994) Three-dimensional structure of extended chromatin fibers as revealed by tapping-mode scanning force microscopy. Proc Natl Acad Sci U S A 91:11621-5
Zlatanova, J; Leuba, S H; Yang, G et al. (1994) Linker DNA accessibility in chromatin fibers of different conformations: a reevaluation. Proc Natl Acad Sci U S A 91:5277-80
van Holde, K; Zlatanova, J (1994) Unusual DNA structures, chromatin and transcription. Bioessays 16:59-68
Leuba, S H; Zlatanova, J; van Holde, K (1993) On the location of histones H1 and H5 in the chromatin fiber. Studies with immobilized trypsin and chymotrypsin. J Mol Biol 229:917-29
Krylov, D; Leuba, S; van Holde, K et al. (1993) Histones H1 and H5 interact preferentially with crossovers of double-helical DNA. Proc Natl Acad Sci U S A 90:5052-6

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