Abstract
Background:
Canonical Notch signaling is initiated when ligand binding induces proteolytic release of the intracellular part of Notch (ICN) from the cell membrane. ICN then travels into the nucleus where it drives the assembly of a transcriptional activation complex containing the DNA-binding transcription factor CSL, ICN, and a specialized co-activator of the Mastermind family. A consensus DNA binding site motif for the CSL protein was previously defined using selection-based methods, but whether subsequent association of Notch and Mastermind-like proteins affects the DNA binding preferences of CSL has not previously been examined.
Principal findings:
Here, we utilized protein-binding microarrays (PBMs) to compare the binding site preferences of isolated CSL with the preferred binding sites of CSL when bound to the CSL-binding domains of all four different human Notch receptors. Measurements were taken both in the absence and in the presence of Mastermind-like-1 (MAML1). Our data show no detectable difference in the DNA binding site preferences of CSL before and after loading of Notch and MAML1 proteins.
Conclusions/significance:
These findings support the conclusion that accrual of Notch and MAML1 promote transcriptional activation without dramatically altering the preferred sites of DNA binding, and illustrate the potential of PBMs to analyze the binding site preferences of multiprotein-DNA complexes.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Algorithms
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Base Sequence
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Binding Sites / genetics
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Binding, Competitive
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DNA / genetics
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DNA / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Glutathione Transferase / genetics
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Glutathione Transferase / metabolism
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Humans
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Immunoglobulin J Recombination Signal Sequence-Binding Protein / genetics
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Immunoglobulin J Recombination Signal Sequence-Binding Protein / metabolism*
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Microarray Analysis / methods
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Oligonucleotides / genetics
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Oligonucleotides / metabolism
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Protein Binding
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism
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Receptor, Notch1 / genetics
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Receptor, Notch1 / metabolism
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Receptor, Notch2 / genetics
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Receptor, Notch2 / metabolism
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Receptor, Notch3
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Receptor, Notch4
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Receptors, Notch / genetics
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Receptors, Notch / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
Substances
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DNA-Binding Proteins
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Immunoglobulin J Recombination Signal Sequence-Binding Protein
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MAML1 protein, human
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NOTCH1 protein, human
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NOTCH2 protein, human
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NOTCH3 protein, human
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NOTCH4 protein, human
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Oligonucleotides
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Proto-Oncogene Proteins
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RBPJ protein, human
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Receptor, Notch1
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Receptor, Notch2
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Receptor, Notch3
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Receptor, Notch4
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Receptors, Notch
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Recombinant Fusion Proteins
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Transcription Factors
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DNA
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Glutathione Transferase