Distribution and characterization of helix-loop-helix enhancer-binding proteins from pancreatic beta cells and lymphocytes.
AUTOR(ES)
Aronheim, A
RESUMO
Transcription of a number of mammalian genes is controlled in part by closely-related DNA elements sharing a CAxxTG consensus sequence (E boxes). In this report, we survey cell extracts from a variety of mammalian cell lineages for ability to bind to the E box denoted IEB1/kappa E1, which plays an important role in expression of both insulin and immunoglobulin kappa genes. Insulin enhancer factor 1 (IEF1), a binding activity previously identified in beta cells, was also present in pituitary endocrine cells but absent in 7 other mammalian cell lines tested. A distinct binding activity, lymphoid enhancer factor 1 (LEF1), was observed in several lymphoid cell lines, but was absent from all nonlymphoid cells tested. IEF1 and LEF1 were distinct according to electrophoretic mobility, and DNA binding specificity. As previously reported, both beta cell and lymphoid cell factors are recognized by antibodies to helix-loop-helix (HLH) proteins, indicating that they may contain functional helix-loop-helix dimerization domains. To directly demonstrate this, we showed that the binding factors are able to interact in vitro with the HLH domain of a characterized HLH protein. These results support the notion that HLH proteins play a key role in cell-specific transcriptional regulation in cells from endocrine and lymphocyte lineages.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=328480Documentos Relacionados
- Enhancer-binding activity of the tal-1 oncoprotein in association with the E47/E12 helix-loop-helix proteins.
- Target Specificities of Drosophila Enhancer of split Basic Helix-Loop-Helix Proteins
- Pancreatic beta-cell-type-specific transcription of the insulin gene is mediated by basic helix-loop-helix DNA-binding proteins.
- An overview of the basic helix-loop-helix proteins
- Seven Genes of the Enhancer of Split Complex of Drosophila Melanogaster Encode Helix-Loop-Helix Proteins