Stat3 and c-Myc Genome-Wide Promoter Occupancy in Embryonic Stem Cells

Abstract

Embryonic stem (ES) cell pluripotency is regulated in part by transcription factor (TF) pathways that maintain self-renewal and inhibit differentiation. Stat3 and c-Myc TFs are essential for maintaining mouse ES cell self-renewal. c-Myc, together with Oct4, Sox2, and Klf4, is a reprogramming factor. While previous studies have investigated core transcriptional circuitry in ES cells, other TF pathways that promote ES cell pluripotency have yet to be investigated. Therefore, to further understand ES cell transcriptional networks, we used genome-wide chromatin immunoprecipitation and microarray analysis (ChIP-chip) to map Stat3 and c-Myc binding targets in ES cells. Our results show that Stat3 and c-Myc occupy a significant number of genes whose expression is highly enriched in ES cells. By comparing Stat3 and c-Myc target genes with gene expression data from undifferentiated ES cells and embryoid bodies (EBs), we found that Stat3 binds active and inactive genes in ES cells, while c-Myc binds predominantly active genes. Moreover, the transcriptional states of Stat3 and c-Myc targets are correlated with co-occupancy of pluripotency-related TFs, polycomb group proteins, and active and repressive histone modifications. We also provide evidence that Stat3 targets are differentially expressed in ES cells following removal of LIF, where culture of ES cells in the absence of LIF resulted in downregulation of Stat3 target genes enriched in ES cells, and upregulation of lineage specific Stat3 target genes. Altogether, we reveal transcriptional targets of two key pluripotency-related genes in ES cells – Stat3 and c-Myc, thus providing further insight into the ES cell transcriptional network.

IL-27 is required for shaping the magnitude, affinity distribution, and memory of T cells responding to subunit immunization

“…IL-27RαKO OT-1 T cells had an early and persistent decrease in Eomes expression (Fig. 4G), consistent with previous reports demonstrating the ability of IL-27 to amplify Eomes expression via STAT3 (28,35). We confirmed the functional significance of this reduced Eomes expression by observing a subsequent reduction in the expression of CD122 (Fig.…”

The transcriptional regulation of pluripotency

“…The Myc module which consists of c-Myc, n-Myc, Rex1, Zfx and E2f1, is known to be involved in selfrenewal and cell metabolism [42][43][44]. Although approximately one-third of all active ESC genes are bound by both c-Myc and the core ESC pluripotency factors [45], the functions of these two modules in gene regulation appear to differ.…”

Function of KLF4 in Stem Cell Biology

“…Oct4, Sox2, and Nanog are all thought to be the master regulators of ES cell pluripotency. Although Oct4 and Sox2 are not direct targets of Stat3 [49], they have been identified as two essential transcription factors that form a heterodimer which binds to the Nanog promoter and regulates the expression of downstream genes that contribute to the maintenance of self-renewal [50]. KLF4 acts as a fast responding mediator to LIF-Stat3 signal changes, and directly binds to the promoter of Nanog to help Oct4 and Sox2 in regulating the expression of Nanog [51].…”