Linker histone partial phosphorylation : effects on secondary structure and chromatin condensation
Lopez Ramos, Rita (Universitat Autònoma de Barcelona. Departament de Bioquímica i de Biologia Molecular)
Sarg, Bettina (Innsbruck Medical University. Biocenter. Division of Clinical Biochemistry)
Lindner, Herbert (Innsbruck Medical University. Biocenter. Division of Clinical Biochemistry)
Bartolomé Piñol, Salvador (Universitat Autònoma de Barcelona. Laboratori de Luminiscència i Espectroscòpia de Biomolècules)
Ponte Marull, Immaculada (Universitat Autònoma de Barcelona. Departament de Bioquímica i de Biologia Molecular)
Suau León, Pere (Universitat Autònoma de Barcelona. Departament de Bioquímica i de Biologia Molecular)
Roque Córdova, Alicia (Universitat Autònoma de Barcelona. Departament de Bioquímica i de Biologia Molecular)

Date:	2015
Abstract:	Linker histones are involved in chromatin higher-order structure and gene regulation. We have successfully achieved partial phosphorylation of linker histones in chicken erythrocyte soluble chromatin with CDK2, as indicated by HPCE, MALDI-TOF and Tandem MS. We have studied the effects of linker histone partial phosphorylation on secondary structure and chromatin condensation. Infrared spectroscopy analysis showed a gradual increase of β-structure in the phosphorylated samples, concomitant to a decrease in α-helix/turns, with increasing linker histone phosphorylation. This conformational change could act as the first step in the phosphorylation-induced effects on chromatin condensation. A decrease of the sedimentation rate through sucrose gradients of the phosphorylated samples was observed, indicating a global relaxation of the 30-nm fiber following linker histone phosphorylation. Analysis of specific genes, combining nuclease digestion and qPCR, showed that phosphorylated samples were more accessible than unphosphorylated samples, suggesting local chromatin relaxation. Chromatin aggregation was induced by MgCl and analyzed by dynamic light scattering (DLS). Phosphorylated chromatin had lower percentages in volume of aggregated molecules and the aggregates had smaller hydrodynamic diameter than unphosphorylated chromatin, indicating that linker histone phosphorylation impaired chromatin aggregation. These findings provide new insights into the effects of linker histone phosphorylation in chromatin condensation.
Grants:	Ministerio de Ciencia e Innovación BFU/2008-00460
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	Nucleic acids research, Vol. 43, Núm. 9 (May 2015) , p. 4463-4476, ISSN 1362-4962

DOI: 10.1093/nar/gkv304
PMID: 25870416

14 p, 3.6 MB

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