Project description:The transcription factor Pax5 is essential for B cell commitment in the mouse, where it represses lineage-inappropriate gene expression, while simultaneously activating the B cell gene expression program. We have performed a global gene expression screen of wild type and Pax5-deficient pro-B cells in an attempt to identify the crucial Pax5 targets in early B-lymphopoiesis. We have also included Rag1-/- and wild type (+/+) proB cells starved of the cytokine IL-7 for 4 hours as controls. Rag1-/- proB cells are incapable of further differentiation due to an absence of immunoglobulin recombination and IL-7 is the major cytokine regulating proB cell growth. Keywords: comparison of genetically modified cell-lines
Project description:Pax5 controls the identity and development of B cells by repressing lineage-inappropriate genes and activating B-cell-specific genes. Here, we used genome-wide approaches to identify Pax5 target genes in pro-B and mature B cells. In these cell types, Pax5 bound to 40% of the cis- regulatory elements defined by mapping Dnase I hypersensitive (DHS) sites, transcription start sites and histone modifications. Although Pax5 bound to 8,000 target genes, it regulated only 4% of them in pro-B and mature B cells by inducing enhancers at activated genes and eliminating DHS sites at repressed genes. Pax5-regulated genes in pro-B cells account for 23% of all expression changes occurring between common lymphoid progenitors and committed pro-B cells, which identifies Pax5 as an important regulator of this developmental transition. Regulated Pax5 target genes minimally overlap in pro-B and mature B cells, which reflects massive expression changes between these cell types. Hence, Pax5 controls B cell identity and function by regulating distinct target genes in early and late B lymphopoiesis. 44 samples (16 RNA-seq, 15 ChIP-seq, 6 DHS-seq, 5 Bio-ChIP-seq, 2 CAGE-seq). All but four samples in in 2 biological replicates (8819, 8275, 8095, 8666). WT and experimental samples are provided.
Project description:PAX5 is a tumor suppressor in B-ALL, while the role of PAX5 fusion proteins in B-ALL development is largely unknown. Here we studied the function of PAX5-ETV6 and PAX5- FOXP1 in mice expressing these proteins from the Pax5 locus. Both proteins arrested Blymphopoiesis at the pro-B-to-pre-B cell transition and, contrary to their proposed dominantnegative role, did not interfere with the expression of most Pax5 target genes. Pax5-Etv6, but not Pax5-Foxp1, cooperated with loss of the Cdkna2a/b tumor suppressor in promoting B-ALL development. Regulated Pax5-Etv6 target genes identified in these B-ALLs encode proteins implicated in pre-BCR signaling and migration/adhesion, which could contribute to the proliferation, survival and tissue infiltration of leukemic B-cells. Together with similar observations made in human PAX5-ETV6+ B-ALLs, these data identified PAX5-ETV6 as a potent oncoprotein. 36 samples in total: A) 24 RNA-Seq samples in 5 cell types: pro-B (5 genotypes, 2-4 replicates) large pre-B (2 genotypes, 2 replicates each) small pre-B (1 genotype, 2 replicates) lymph node (1 genotype, 3 replicates) bone marrow (1 genotype, 2 replicates) B) 12 ChIP-Seq samples in 2 cell types: pro-B (H3K27me3, H3K9ac, H3K4me2, H3K4me3, H3K27ac, 1 replicate each; Pax5Etv6 ChIP, Prd ChIP, 2 replicates each; Pax5 ChIP 1 replicate) lymph node (1 genotype, 2 replicates).
