Prof. Jose L. Gómez Skarmeta
Universidad Pablo de Olavide, Sevilla, Spain
Enhancer dynamics during vertebrate development and its influence on the genomic architecture
The generation of distinctive cell types that form different tissues and organs requires precise, temporal and spatial control of gene expression. This depends on specific cis-regulatory elements distributed in the non-coding DNA surrounding their target genes. Studies performed on mammalian embryonic stem cells suggest that active enhancers form part of a defined chromatin landscape marked by histone H3 lysine 4 mono-methylation (H3K4me1) and histone H3 lysine 27 acetylation (H3K27ac). Nevertheless, it remains unclear how the dynamics of these histone modifications correlate with developmental processes during vertebrate embryogenesis. We have generated the zebrafish genomic maps of H3K4me1/me3 and H3K27ac at four developmental time-points and analyze embryonic enhancer activity. We find that: (i) changes in H3K27ac enrichment at enhancers accompany the shift from pluripotency to tissue-specific gene expression; (ii) the three-dimensional structure of genomic loci during early development is governed by CTCF rather than by dynamics of H3K4me1 and H3K27ac. This indicates that enhancer activity, essential for developmental progression, is likely regulated within the constraints of chromosomal architecture that becomes gradually defined during embryogenesis.
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