Abstract
Previous studies have suggested that the early-B-cell-specific mb-1(Igalpha) promoter is regulated by EBF and Pax-5. Here, we used in vivo footprinting assays to detect occupation of binding sites in endogenous mb-1 promoters at various stages of B-cell differentiation. In addition to EBF and Pax-5 binding sites, we detected occupancy of a consensus binding site for E2A proteins (E box) in pre-B cells. EBF and E box sites are crucial for promoter function in transfected pre-B cells, and EBF and E2A proteins synergistically activated the promoter in transfected HeLa cells. Other data suggest that EBF and E box sites are less important for promoter function at later stages of differentiation, whereas binding sites for Pax-5 (and its Ets ternary complex partners) are required for promoter function in all mb-1-expressing cells. Using DNA microarrays, we found that expression of endogenous mb-1 transcripts correlates most closely with EBF expression and negatively with Id1, an inhibitor of E2A protein function, further linking regulation of the mb-1 gene with EBF and E2A. Together, our studies demonstrate the complexity of factors regulating tissue-specific transcription and support the concept that EBF, E2A, and Pax-5 cooperate to activate target genes in early B-cell development.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Antigens, CD / genetics
-
Antigens, CD / metabolism*
-
B-Lymphocytes / physiology*
-
Base Sequence
-
Basic Helix-Loop-Helix Transcription Factors
-
Binding Sites
-
CD79 Antigens
-
Cell Line
-
DNA Footprinting
-
DNA-Binding Proteins / genetics
-
DNA-Binding Proteins / metabolism*
-
Gene Expression Regulation
-
Genes, Reporter
-
Helix-Loop-Helix Motifs
-
Humans
-
Macromolecular Substances
-
Mice
-
Molecular Sequence Data
-
Mutation
-
Nuclear Proteins / genetics
-
Nuclear Proteins / metabolism
-
Oligonucleotide Array Sequence Analysis
-
PAX5 Transcription Factor
-
Promoter Regions, Genetic*
-
Protein Binding
-
Receptors, Antigen, B-Cell / genetics
-
Receptors, Antigen, B-Cell / metabolism*
-
Recombinant Fusion Proteins / metabolism
-
Trans-Activators / genetics
-
Trans-Activators / metabolism*
-
Transcription Factors / genetics
-
Transcription Factors / metabolism*
-
Transcription, Genetic
Substances
-
Antigens, CD
-
Basic Helix-Loop-Helix Transcription Factors
-
CD79 Antigens
-
CD79A protein, human
-
Cd79a protein, mouse
-
DNA-Binding Proteins
-
EBF1 protein, human
-
Ebf1 protein, mouse
-
Macromolecular Substances
-
Nuclear Proteins
-
PAX5 Transcription Factor
-
PAX5 protein, human
-
Pax5 protein, mouse
-
Receptors, Antigen, B-Cell
-
Recombinant Fusion Proteins
-
TCF3 protein, human
-
Trans-Activators
-
Transcription Factors