Histone tail acetylation in brain occurs in an unpredictable fashion after death

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Histone tail acetylation in brain occurs in an unpredictable fashion after death Marta Barrachina • Jesu´s Moreno • Izaskun Villar-Mene´ndez • Salvador Juve´s Isidre Ferrer



Received: 21 August 2011 / Accepted: 8 September 2011 / Published online: 16 September 2011 Ó Springer Science+Business Media B.V. 2011

Abstract Histone acetylation plays a role in the regulation of gene transcription. Yet it is not known whether post-mortem brain tissue is suitable for the analysis of histone acetylation. To examine this question, nucleosomes were isolated from frontal cortex of nine subjects which were obtained at short times after death and immediately frozen at -80°C or maintained at room temperature from 3 h up to 50 h after death and then frozen at -80°C to mimic variable post-mortem delay in tissue processing as currently occurs in normal practice. Chromatin immunoprecipitation assays were performed for two lysine residues,

H3K9ac and H3K27ac. Four gene loci were amplified by SyBrGreen PCR: Adenosine A2A receptor, UCHL1, a-synuclein and b-globin. Results showed variability in the histone acetylation level along the post-mortem times and an increase in the acetylation level at an unpredictable time from one case to another and from one gene to another within the first 24 h of postmortem delay. Similar results were found with three rat brains used to exclude the effects of agonal state and to normalize the start-point as real time zero. Therefore, the present observations show that human post-mortem brain is probably not suitable for comparative studies of histone acetylation.

Electronic supplementary material The online version of this article (doi:10.1007/s10561-011-9278-9) contains supplementary material, which is available to authorized users.

Keywords Histone acetylation  Post-mortem delay  UCHL1  ADORA2A  a-Synuclein  b-Globin

M. Barrachina (&)  J. Moreno  I. Villar-Mene´ndez  S. Juve´s  I. Ferrer Institute of Neuropathology, [Bellvitge Biomedical Research Institute-] IDIBELL, Bellvitge University Hospital-ICS, c/Feixa Llarga s/n, 08908 L’Hospitalet de Llobregat, Spain e-mail: [email protected] M. Barrachina  J. Moreno  S. Juve´s  I. Ferrer Centro de Investigacio´n Biome´dica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), L’Hospitalet de Llobregat, Spain I. Ferrer Unitat de Neuropatologia Experimental, Departament de Patologia i Terape`utica Experimental, Universitat de Barcelona, L’Hospitalet de Llobregat, Spain

Introduction Eukaryotic DNA is wrapped around nucleosomes to form a structure that facilitates packaging of chromatin. The nucleosome core consists of 147 bp of DNA enfolded by an octamer of the core histones H2A, H2B, H3 and H4 (Luger et al. 1997). Several covalent modifications in the N-terminus of histone tails such as methylation, acetylation, phosphorylation, ubiquitination and polyADP ribosylation control the transition from tightly protected chromatin to freely accessible DNA, and, therefore, control gene expression. It has

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been established that histone m