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Methyl CpG level at distal part of heat‐shock protein promoter HSP 70 exhibits epigenetic memory for heat stress by modulating recruitment of POU 2F1‐associated nucleosome‐remodeling deacetylase (Nu RD ) complex
Author(s) -
Kisliouk Tatiana,
Cramer Tomer,
Meiri Noam
Publication year - 2017
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.14014
Subject(s) - epigenetics , dna methylation , heat shock protein , biology , hsf1 , microbiology and biotechnology , heat shock , hsp70 , gene expression , genetics , gene
Abstract Depending on its stringency, exposure to heat in early life leads to either resilience or vulnerability to heat stress later in life. We hypothesized that epigenetic alterations in genes belonging to the cell proteostasis pathways are attributed to long‐term responses to heat stress. Epigenetic regulation of the mRNA expression of the molecular chaperone heat‐shock protein ( HSP ) 70 ( HSPA 2) was evaluated in the chick hypothalamus during the critical period of thermal‐control establishment on day 3 post‐hatch and during heat challenge on day 10. Both the level and duration of HSP 70 expression during heat challenge a week after heat conditioning were more pronounced in chicks conditioned under harsh versus mild temperature. Analyzing different segments of the promoter in vitro indicated that methylation of a distal part altered its transcriptional activity. In parallel, DNA ‐methylation level of this segment in vivo was higher in harsh‐ compared to mild‐heat‐conditioned chicks. Hypermethylation of the HSP 70 promoter in high‐temperature‐conditioned chicks was accompanied by a reduction in both POU Class 2 Homeobox 1 ( POU 2F1) binding and recruitment of the nucleosome remodeling deacetylase (Nu RD ) chromatin‐remodeling complex. As a result, histone H3 acetylation levels at the HSP 70 promoter were higher in harsh‐temperature‐conditioned chicks than in their mild‐heat‐conditioned counterparts. These results suggest that methylation level of a distal part of the HSP 70 promoter and POU 2F1 recruitment may reflect heat‐stress‐related epigenetic memory and may be useful in differentiating between individuals that are resilient or vulnerable to stress.