E2A expression, nuclear localization, and in vivo formation of DNA- and non-DNA-binding species during B-cell development.
A monoclonal antibody (Yae) was characterized and shown to specifically recognize E2A proteins in vivo, including the E2A-Pbx1 fusion gene products, p77E2A-Pbx1 and p85E2A-Pbx1. E2A proteins of a predominant molecular mass of 72 kDa, which comigrated with in vitro-produced rat E12 and and rat E47, were detected in human pro-B, pre-B, mature B, and plasma cell lines. The Yae antibody detected an E2A-containing microE2 enhancer element-binding complex (BCF-1) in pre-B- and mature B-cell lines in electrophoretic mobility shift assays which displayed a migration rate similar to that of in vitro-produced rat E12 and rat E47. A new E2A-containing microE2-binding species (P-E2A) was identified in plasma cells by using electrophoretic mobility shift assays. E2A proteins were detected in pro-B cells but were unable to bind the microE2 site. These observations suggest that the microE2 site is the target of stage-specific E2A regulatory complexes during B-cell development. Immunostaining analyses demonstrated the predominant nuclear localization of E2A proteins. Finally, we have identified an E2A form, designated I-E2A, which is unable to bind DNA. Our observations demonstrate novel in vivo mechanisms for the regulation of transcription by E2A proteins during B-cell development.
Jacobs
Y
Y
Department of Biochemistry, University of California, Riverside 92521.
Vierra
C
C
Nelson
C
C
D000818:Animals; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D001483:Base Sequence; D002454:Cell Differentiation; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005786:Gene Expression Regulation; D005803:Genes, Immunoglobulin; D006801:Humans; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D010950:Plasma Cells / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism; D051820:TCF Transcription Factors; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors
D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; D015345:Oligonucleotide Probes; D011993:Recombinant Fusion Proteins; D051820:TCF Transcription Factors; C544912:TCF7L1 protein, human; C553060:Tcf7l1 protein, rat; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D004247:DNA