The Myc-associated zinc finger protein epigenetically controls expression of interferon-γ-stimulated genes by recruiting STAT1 to chromatin.

The MYC-Associated Zinc Finger Protein (MAZ) plays important roles in chromatin organization and gene transcription regulation. Dysregulated expression of MAZ causes diseases, such as glioblastoma, breast cancer, prostate cancer, and liposarcoma. Previously, it has been reported that MAZ controls the proinflammatory response in colitis and colon cancer via STAT3 signaling, suggesting that MAZ is involved in regulating immunity-related pathways. However, the molecular mechanism underlying this regulation remains elusive. Here, we investigate the regulatory effect of MAZ on interferon-gamma (IFN-γ)-stimulated genes via STAT1, a protein that plays an essential role in immune responses to viral, fungal, and mycobacterial pathogens. We demonstrate that about 80% of occupied STAT1-binding sites colocalize with occupied MAZ-binding sites in HAP1/K562 cells after IFN-γ stimulation. MAZ depletion significantly reduces STAT1 binding in the genome. By analyzing genome-wide gene expression profiles in the RNA-Seq data, we show that MAZ depletion significantly suppresses a subset of the immune response genes, which include the IFN-stimulated genes IRF8 and Absent in Melanoma 2. Furthermore, we find that MAZ controls expression of the immunity-related genes by changing the epigenetic landscape in chromatin. Our study reveals an important role for MAZ in regulating immune-related gene expression.

The RNA helicases DDX5 and DDX17 facilitate neural differentiation of human pluripotent stem cells NTERA2.

AIMS: Understanding human neurogenesis is critical toward regenerative medicine for neurodegeneration. However, little is known how neural differentiation is regulated by DEAD box-containing RNA helicases, which comprise a diverse class of RNA remodeling enzymes. MATERIALS AND METHODS: ChIP-seq was utilized to identify binding sites of DDX5 and DDX17 in both human pluripotent stem cell (hPSC) line NTERA2 and their retinoic acid-induced neural derivatives. RNA-seq was used to elucidate genes differentially expressed upon depletion of DDX5 and DDX17. Neurosphere assay, flow cytometry, and immunofluorescence staining were performed to test the effect of depletion of the two RNA helicases in neural differentiation. KEY FINDINGS: We show here that expression of DDX5 and DDX17 is abundant throughout neural differentiation of NTERA2, and is mostly localized within the nucleus. The two RNA helicases occupy chromatin genome-wide at regions associated with neurogenesis-related genes in both hPSCs and their neural derivatives. Further, both DDX5 and DDX17 are mutually required for controlling transcriptional expression of these genes, but are not important for maintenance of stem cell state of hPSCs. In contrast, they facilitate early neural differentiation of hPSCs, generation of neurospheres from the stem cells, and transcriptional expression of key neurogenic transcription factors such as SOX1 and PAX6 during neural differentiation. Importantly, DDX5 and DDX17 are critical for differentiation of hPSCs toward NESTIN- and TUBB3-positive cells, which represent neural progenitors and mature neurons, respectively. SIGNIFICANCE: Collectively, our findings suggest the role of DDX5 and DDX17 in transcriptional regulation of genes involved in neurogenesis, and hence in neural differentiation of hPSCs.

Increased CD1c+ mDC1 with mature phenotype regulated by TNFα-p38 MAPK in autoimmune ocular inflammatory disease.

In this study we investigated the role of blood CD1c(+) myeloid dendritic cells 1 (mDC1), a key mDC subtype, in patients with autoimmune uveitis. We observed a significant increase of blood CD1c(+) mDC1 in uveitis patients. The increased CD1c(+) mDC1 exhibited high HLADR expression and less antigen uptake. CD1c(+) mDC1 were divided into two subpopulations. CD1c(hi) mDC1 subpopulation showed less antigen uptake and higher HLADR expression compared to CD1c(lo) mDC1 subpopulation. Importantly, the CD1c(hi) mDC1 subpopulation was increased in uveitis patients. In vitro, mature monocyte-derived dendritic cells (MoDCs), characterized by lower levels of antigen uptake, induced more CD4(+)CD62L(-) T helper cell proliferation. The mature phenotype and function of CD1c(+) mDC1 were regulated by TNFα via a p38 MAPK-dependent pathway. These data show that alterations in the systemic immune response are involved in the pathogenesis of autoimmune uveitis and invite the therapeutic possibility of attenuating uveitis by manipulating blood CD1c(+) mDC1.

Phosphorylation of RNA polymerase II CTD regulates H3 methylation in yeast.

Histone methylation is now realized to be a pivotal regulator of gene transcription. Although recent studies have shed light on a trans-histone regulatory pathway that controls H3 Lys 4 and H3 Lys 79 methylation in Saccharomyces cerevisiae, the regulatory pathway that affects Set2-mediated H3 Lys 36 methylation is unknown. To determine the functions of Set2, and identify factors that regulate its site of methylation, we genomically tagged Set2 and identified its associated proteins. Here, we show that Set2 is associated with Rbp1 and Rbp2, the two largest subunits of RNA polymerase II (RNA pol II). Moreover, we find that this association is specific for the interaction of Set2 with the hyperphosphorylated form of RNA pol II. We further show that deletion of the RNA pol II C-terminal domain (CTD) kinase Ctk1, or partial deletion of the CTD, results in a selective abolishment of H3 Lys 36 methylation, implying a pathway of Set2 recruitment to chromatin and a role for H3 Lys 36 methylation in transcription elongation. In support, chromatin immunoprecipitation assays demonstrate the presence of Set2 methylation in the coding regions, as well as promoters, of genes regulated by Ctk1 or Set2. These data document a new link between histone methylation and the transcription apparatus and uncover a regulatory pathway that is selective for H3 Lys 36 methylation.