Differential interaction of nuclear factors with the leukocyte-specific pp52 promoter in B and T cells
Autor: | S A, Omori, S, Smale, A, O'Shea-Greenfield, R, Wall |
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Rok vydání: | 1997 |
Předmět: |
Oncogene Proteins
Base Sequence Proto-Oncogene Proteins c-ets Transcription Genetic Sp1 Transcription Factor Calcium-Binding Proteins Microfilament Proteins Molecular Sequence Data Nuclear Proteins Cell Line DNA-Binding Proteins CCAAT-Enhancer-Binding Proteins Humans Lymphocytes Promoter Regions Genetic Transcription Factors |
Zdroj: | Journal of immunology (Baltimore, Md. : 1950). 159(4) |
ISSN: | 0022-1767 |
Popis: | The leukocyte-specific, cytoskeleton-binding pp52 (LSP-1, WP-34) protein is widely expressed in multiple leukocyte lineages, including B and T lymphocytes, granulocytes, and macrophages. We previously detected a tissue-specific promoter preceding the exon encoding the N terminus of the pp52 leukocyte protein. Here we describe the functional characterization of this promoter and identification of the factors in B and T cells that regulate its activity. The pp52 promoter contains an initiator specifying the unique 5' terminus of pp52 mRNA, tandem pairs of Ets and SP1 motifs, and a lone C/EBP motif. All these motifs are essential and collectively control transcriptional activity. DNA binding studies and Ab supershift assays revealed that different combinations of factors interact with these motifs in B cells vs T cells. The Ets motifs are preferentially bound by PU-1 in B cell extracts from all stages of development, whereas a different Ets family member reacts with these motifs in T cell extracts. The C/EBP motif is bound by Ig/EBP-1 in pre-B cell and T cell extracts, but is replaced by nuclear factor-IL-6beta or a nuclear factor-IL-6beta-Ig/EBP-1 heterodimer in plasmacytoma cell extracts. Despite its reported role as a negative regulator of transcription, Ig/EBP-1 appears to exert a stimulatory effect on this promoter. These findings reveal the features controlling the pp52 promoter in B and T cells and provide the foundation for determining the regulation of this promoter in other leukocyte lineages. |
Databáze: | OpenAIRE |
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