Single-molecule analysis of combinatorial epigenomic states in normal and tumor cells.
Proc Natl Acad Sci U S A
; 110(19): 7772-7, 2013 May 07.
Article
em En
| MEDLINE
| ID: mdl-23610441
ABSTRACT
Proper placement of epigenetic marks on DNA and histones is fundamental to normal development, and perturbations contribute to a variety of disease states. Combinations of marks act together to control gene expression; therefore, detecting their colocalization is important, but because of technical challenges, such measurements are rarely reported. Instead, measurements of epigenetic marks are typically performed one at a time in a population of cells, and their colocalization is inferred by association. Here, we describe a single-molecule analytical approach that can perform direct detection of multiple epigenetic marks simultaneously and use it to identify mechanisms coordinating placement of three gene silencing marks, trimethylated histone H3 lysine 9, lysine 27 (H3K9me3, H3K27me3), and cytosine methylation (mC), in the normal and cancer genome. We show that H3K9me3 and mC are present together on individual chromatin fragments in mouse embryonic stem cells and that half of the H3K9me3 marks require mC for their placement. In contrast, mC and H3K27me3 coincidence is rare, and in fact, mC antagonizes H3K27me3 in both embryonic stem cells and primary mouse fibroblasts, indicating this antagonism is shared among primary cells. However, upon immortalization or tumorigenic transformation of mouse fibroblasts, mC is required for complete H3K27me3 placement. Importantly, in human promyelocytic cells, H3K27me3 is also dependent on mC. Because aberrant placement of gene silencing marks at tumor suppressor genes contributes to tumor progression, the improper dependency of H3K27me3 by mC in immortalized cells is likely to be fundamental to cancer. Our platform can enable other studies involving coordination of epigenetic marks and leverage efforts to discover disease biomarkers and epigenome-modifying drugs.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Histonas
/
Regulação Neoplásica da Expressão Gênica
/
Epigênese Genética
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Estados Unidos