Transcription factor ZBTB7A-deficiency effect on U87MG cells in vitro
Ontology highlight
ABSTRACT: Analysis of glioblastoma cell line U87MG depleted for ZBTB7A (Zinc Finger and BTB Domain Containing 7A, also known as FBI1, POKEMON or LRF). ZBTB7A is transcription factor that represses the transcription of a wide range of genes involved in cell proliferation and differentiation. Results provide insight into the role of ZBTB7A in glioblastoma.
Project description:Zinc finger and BTB domain containing transcription repressor ZBTB7A has been recently reported as a tumor suppressor who plays important functions to prevent the progression of prostate cancer. However, the chromatin activity of ZBTB7A in prostate cancer cells remain unclear. In order to identify the cistrome and transcriptome of ZBTB7A, we performed ZBTB7A ChIP-seq in VCaP cells and RNA-seq in VCaP cells transfected with siRNA targeting ZBTB7A or non-targeting control, respectively (cells were grown in full serum). By using combined ChIP-seq and RNA-seq analyses in VCaP cells, we have precisely mapped the ZBTB7A binding sites and identified a subset of genes that are directly repressed by ZBTB7A. To study the chromatin interaction of ZBTB7A with androgen receptor (AR), we also performed ChIP-seq of ZBTB7A in VCaP cells stimulated with 10 nM DHT for 4 hours versus vehicle control (cells were hormone-depleted prior to DHT stimulation). Our results show that ZBTB7A binding is increased by androgen at AR and ZBTB7A overlapping sites.
Project description:Zinc finger and BTB domain containing transcription repressor ZBTB7A has been recently reported as a tumor suppressor who plays important functions to prevent the progression of prostate cancer. However, the chromatin activity of ZBTB7A in prostate cancer cells remain unclear. In order to identify the cistrome and transcriptome of ZBTB7A, we performed ZBTB7A ChIP-seq in VCaP cells and RNA-seq in VCaP cells transfected with siRNA targeting ZBTB7A or non-targeting control, respectively (cells were grown in full serum). By using combined ChIP-seq and RNA-seq analyses in VCaP cells, we have precisely mapped the ZBTB7A binding sites and identified a subset of genes that are directly repressed by ZBTB7A. To study the chromatin interaction of ZBTB7A with androgen receptor (AR), we also performed ChIP-seq of ZBTB7A in VCaP cells stimulated with 10 nM DHT for 4 hours versus vehicle control (cells were hormone-depleted prior to DHT stimulation). Our results show that ZBTB7A binding is increased by androgen at AR and ZBTB7A overlapping sites.
Project description:LRF, which is encoded by the ZBTB7A gene and formerly known as POKEMON (POK erythroid myeloid ontogenic factor), was originally identified as a PLZF (promyelocytic leukemia zinc finger) homologue interacting with BCL6 (B-cell lymphoma 6). LRF is a transcription factor that is broadly expressed in hematopoietic lineage cells, but its expression is particularly high in erythroblasts and germinal center (GC) B-cells. The goal of this study is to assess the effect of LRF loss on the LT-HSC transcriptome. Nine days after injection of adult mice with polyinosinic polycytidylic acid (pIpc) to activate Cre, total RNAs were isolated from double-sorted LT-HSCs from LRF Flox/+ Mx1-Cre+ and LRF Flox/Flox Mx1-Cre+ mice and processed for microarray analysis. We performed gene expression microarray analysis of FACS-sorted LT-HSCs (LSK IL7Ra-Flt3-CD150+CD48-) to assess the effect of Lrf loss on the LT-HSC transcriptome. Zbtb7a Flox/+ Mx1-Cre+ mice were used as a control to normalize the potential effects of Cre recombinase. LT-HSCs were FACS-sorted from three Lrf knockout (Zbtb7a Flox/Flox Mx1-Cre+) and two control (Zbtb7a Flox/+ Mx1-Cre+) mice, nine days after the first pIpC injection.
Project description:Hemoglobinopathies, including sickle cell disease and _-thalassemia, are global public health concerns. Induction of fetal-type hemoglobin (HbF) is a promising means to treat these disorders; however, precisely how HbF expression is silenced in adult erythroid cells is not fully understood. Here, we show that the LRF/ZBTB7A transcription factor is a potent repressor of HbF production. LRF inactivation derepresses embryonic/fetal _-globin expression in mouse and human adult erythroid cells. We employed genome-wide analysis of the transcriptome, chromatin accessibility and LRF occupancy sites, and demonstrate that LRF occupies the _-globin loci and maintains nucleosome density necessary for _-globin silencing. LRF confers its repressive activity through a unique NuRD repressor complex independent of BCL11A. Strikingly, human erythroid lines lacking both LRF and BCL11A exhibited almost a complete switch in expression from adult- to fetal-type globin, suggesting that these two factors cumulatively represent the near entirety of _-globin repressive activity in adult erythroid cells. RNA-seq, LRF ChIP-seq and ATAC-seq assays were used to investigtae LRF binding, effect of LRF depletion on transcription and chromatin landscape in mouse and human cells.
Project description:U87MG is a glioblastoma cell line that shows substantial heterogeneity despite long-term passaging. We used microarrays to identify variations in gene expression that are associated with phenotypic differences among subclones derived from U87MG.
Project description:ChIP-seq for LRF/ZBTB7A in untransfected or LRF/ZBTB7A-overexpressing K562 cells, with or without hemin/EPO treatment and in K562 LRF/ZBTB7A-Knockdown cells
Project description:Hemoglobinopathies, including sickle cell disease and _-thalassemia, are global public health concerns. Induction of fetal-type hemoglobin (HbF) is a promising means to treat these disorders; however, precisely how HbF expression is silenced in adult erythroid cells is not fully understood. Here, we show that the LRF/ZBTB7A transcription factor is a potent repressor of HbF production. LRF inactivation derepresses embryonic/fetal _-globin expression in mouse and human adult erythroid cells. We employed genome-wide analysis of the transcriptome, chromatin accessibility and LRF occupancy sites, and demonstrate that LRF occupies the _-globin loci and maintains nucleosome density necessary for _-globin silencing. LRF confers its repressive activity through a unique NuRD repressor complex independent of BCL11A. Strikingly, human erythroid lines lacking both LRF and BCL11A exhibited almost a complete switch in expression from adult- to fetal-type globin, suggesting that these two factors cumulatively represent the near entirety of _-globin repressive activity in adult erythroid cells.
Project description:B-hemoglobinopathies such as Sickle Cell Disease (SCD) and b-thalassemia result from mutations in the adult b-globin gene. Reactivating the developmentally silenced fetal g-globin gene is a therapeutic goal for treating SCD and b-thalassemia1. Some forms of Hereditary Persistence of Fetal Hemoglobin (HPFH), a rare benign condition in which individuals express g‑globin throughout adulthood, are caused by point mutations in the g‑globin gene promoter at regions residing ~115 and 200 base pairs upstream of the transcription start site. Here we show that the major fetal globin repressors BCL11A and ZBTB7A/LRF directly bind to the -115 and ‑200 sites, respectively. Furthermore, introduction of naturally occurring HPFH mutations into erythroid cells by CRISPR/Cas9 disrupts repressor binding and raises g‑globin expression. These findings resolve the mystery surrounding how these HPFH mutations operate and demonstrate that BCL11A and ZBTB7A/LRF are major direct repressors of the fetal globin gene.
Project description:We established tumorspheres from human glioblastoma U87MG cells by single cell-derived tumorsphere formation. Among these tumorspheres, P4E8 clone showed cancer stem cell like properties such as self-renewal capacity, expression of cancer stem cell markers, resistance to anti-cancer agents and in vivo tumorigenicity. To find novel therapeutic target molecules, we performed differential gene expression analysis between U87MG and P4E8 cells.