Regulation of gene expression by esrrb in embryonic stem cells

Abstract

Embryonic stem (ES) cells can be cultured indefinitely in vitro while retaining the ability to give rise to any cell type within an organism. Through the regulation of gene expression, transcription factors play important roles in maintaining the self-renewing and pluripotent state of ES cells. Nanog is a homeodomain-containing protein that has been identified to be essential both for the early development of the blastocyst and the maintenance of ES cells. The regulatory networks controlled by Nanog reveal that it influences the expression of its downstream genes, many of which are novel factors with unknown function in ES cell biology. In this study, we identified Esrrb (estrogen-related receptor, beta) to be a novel downstream target of Nanog. We demonstrated that RNA interferenceb mediated depletion of Esrrb induced a loss of ES cell morphology, accompanied by a significant reduction of ES cell markers and the de-repression of differentiation genes. We confirmed that Esrrb has DNA binding activity, and characterized its DNA binding motif using EMSA (Electrophoretic mobility shift assay). To further establish the function of Esrrb in ES cells, we constructed the Esrrb regulatory network using a combination of microarray expression profiling and genome-wide location mapping by chromatin immunoprecitation-sequencing assay (ChIP-Solexa). Esrrb regulates a large number of genes involved in ES cell self-renewal and differentiation. Our work may provide new insights into the underlying mechanisms of self-renewal and pluripotency in ES cells.