Differential Functions for the Transcription Factor E2A in Positive and Negative Gene Regulation in Pre-B Lymphocytes

Abstract

The transcription factors encoded by the E2A gene have been shown to play essential roles in the initiation and progression of lymphocyte development. However, there is still a lack of comprehensive understanding of E2A downstream genes in B-cell development. We previously developed a gene tagging-based chromatin immunoprecipitation (ChIP) system to directly evaluate E2A target genes in B-cell development. Here, we have improved this ChIP strategy and used it in conjunction with microarray analysis on E2A-deficient pre-B-cell lines to determine E2A target genes in lymphocyte development. Both microarray data and ChIP studies confirmed that E2A directly controls IgH gene expression. The microarray assay also revealed genes that were significantly up-regulated after E2A disruption. ChIP analysis showed that E2A was most likely to be directly involved in repression of some of these target genes such as Nfil3 and FGFR2. An inducible E2A reconstitution system further demonstrated that E2A-mediated repression of Nfil3 and FGFR2 was reversible. Collectively, these findings indicate that E2A is a positive regulator for one set of genes and a negative regulator for another set of genes in developing B lymphocytes.Lymphocytes develop from multipotent hematopoietic stem cells to provide cell-mediated and humoral immunological protection against foreign antigens. Hematopoietic stem cells give rise to mature B-and T-lymphocytes through a series of well defined and highly ordered differentiation stages in the bone marrow and thymus, respectively (1). These stages are functionally defined by the progressive assembly and expression of the lymphocyte antigen receptors. These antigen receptors are generated through tightly regulated genomic recombination events at the B-and T-lymphocyte antigen receptor loci to establish a diverse pool of receptor specificities (2).Antigen receptor gene recombination and thus lymphocyte differentiation requires the activity of numerous broadly expressed and lineage-specific transcription factors. The basic helix-loop-helix transcription factors encoded by the E2A gene have been identified as essential regulators of gene expression during lymphocyte development (3). The E2A proteins were initially characterized as immunoglobulin heavy (IgH) 1 and light chain enhancer-binding factors and have since been shown to bind consensus E-box motifs (CANNTG) in the promoters and enhancers of numerous lymphoid lineage-specific genes (4, 5). E2A proteins are highly expressed in lymphoid progenitor populations (6) and are required for the initiation of B-lymphocyte development in the bone marrow. Mice deficient for E2A show a complete and persistent block at the earliest stage of B-cell development prior to the initiation of immunoglobulin heavy chain rearrangements (7,8).E2A has been implicated in regulating the expression of multiple BCR complex components, including the surrogate light chain 5, the BCR signaling molecule mb-1, and the immunoglobulin heavy chain (IgH) and k light chain genes (9 -15). Whereas ...

E2A Promotes the Survival of Precursor and Mature B Lymphocytes

“…E2A Ϫ/Ϫ pre-B cells exhibit a block in Ig L chain recombination but retain expression of many B lineage-specific genes including known E2A targets such as EBF, Ig H chain, and mb-1 (13,15). These findings raise the possibility that other E proteins may be able to compensate for the loss of E2A.…”

“…We have previously established E2A-deficient Ab-MuLV transformed progenitor B cell lines to study E2A regulation of pre-B lymphocyte gene expression and differentiation (13,15). E2A Ϫ/Ϫ pre-B cells exhibit a block in Ig L chain recombination but retain expression of many B lineage-specific genes including known E2A targets such as EBF, Ig H chain, and mb-1 (13,15).…”

“…E2A has also been directly implicated in the transcriptional regulation of many B lineage-specific genes and has been shown to be essential for Ig H and L chain recombination (5,(12)(13)(14). Recent studies using E2A-deficient hemopoietic progenitors and pre-B cell lines demonstrate that E2A promotes, as well as suppresses, expression of a broad array of transcripts in B cells (8,15). E2A is required to initiate expression of many B lineage-specific genes such as EBF, mb-1, and B29.…”

Detecting reliable gene interactions by a hierarchy of Bayesian network classifiers

“…Upregulation of the NEUl expression is important for the primary function of macrophages and there is a link between NEUl and the cellular immune response [57]: data show that the differentiation of monocytes into macrophages is associated with the specific upregulation of the enzyme activity of NEUl [58]. Greenbaum et al [59] reported that TCF3 is a negative regulator of a set of genes involved in the development of B lymphocytes, thus, showing the link between TCF3 and NEUl. Table 3 gathers the summary of the dependences that have been previously reported by biological works.…”

Focused transcription from the human CR2/CD21 core promoter is regulated by synergistic activity of TATA and Initiator elements in mature B cells

“…A putative DPE was also identified with a near-consensus sequence (CR2/CD21; AGAGC, consensus; A/G-G-A/ T-C/T-A/C/G) located at 131 to 135 and predicted to bind E2A. E2A is associated with gene expression changes during Bcell development 40 and is essential for the development of pro-, pre-and immature B cells in the bone marrow. 41 To determine if E2A is bound to the CR2/CD21 gene encompassing the DPE in mature B cells, we performed chromatin immunoprecipitation with antibodies specific for the E2A proteins E12 and E47 as well as RNAP as a positive control (Figure 2b).…”