Abstract

The overall aim of this research is an understanding of the forces and interactions that determine and stabilize the structure of the nucleosome and the higher order structure of chromatin. Since reversible modification in these structures must accompany such nuclear processes as chromatin replication and transcription, an understanding of chromatin stability is essential to a complete comprehension of how these processes occur and are controlled in vivo. The problems will be approached through the use of well defined model systems. Nucleosomes and oligonucleosomes will be constructed by reconstitution with histone octamers on cloned DNA fragments containing single or multiple positioning sequences. Either intact chicken erythrocyte histones or histones from which N-terminal tails have been removed by controlled proteolysis will be employed. New methods allow reconstitution with either modified H2A/H2B or H3/H4. With such systems, the following questions will be investigated: (1) What histones, or portions of histones, recognize the positioning signals on DNA sequences? (2) What are the thermodynamic parameters for the dissociation of a defined nucleosome at moderate salt concentrations? What are the contributions of particular histones and portions of histones to nucleosome stability? (3) What are the precise requirements for the extended chain to solenoid transition in chromatin? These experiments will utilize phased, homogeneous oligonucleosomes constructed as above. (4) What roles do the different classes of histone tails play in stabilizing the solenoidal structure?

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM022916-15
Application #
3271401
Study Section
Molecular Biology Study Section (MBY)
Project Start
1979-04-01
Project End
1992-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
15
Fiscal Year
1990
Total Cost
Indirect Cost

  Institution

Name
Oregon State University
Department
Type
Schools of Arts and Sciences
DUNS #
053599908
City
Corvallis
State
OR
Country
United States
Zip Code
97339

  Publications

Robert, C H (1995) Estimating friction coefficients of mixed globular/chain molecules, such as protein/DNA complexes. Biophys J 69:840-8
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
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
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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