Abstract
Myn, a novel murine approximately 18 kd basic/helix-loop-helix/"leucine zipper" (B/HLH/LZ) protein, forms a specific DNA-binding complex with the c-Myc oncoprotein through the HLH/LZ motif in both proteins. c-Myc/Myn recognizes a c-Myc-binding site (GACCACGTGGTC) with higher affinity than either protein by itself. CpG methylation of the recognition site greatly inhibits DNA binding, suggesting that DNA methylation may regulate the c-Myc/Myn complex in vivo. In 3T3 fibroblasts, Myn mRNA levels are induced several-fold by serum with delayed early kinetics, suggesting regulation by immediate-early gene products. Coexpression of Myn in a myc/ras rat embryo fibroblast focus formation assay specifically augmented c-myc transforming activity. We suggest that interaction of Myn with c-Myc stabilizes sequence-specific DNA binding in vivo.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Base Sequence
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
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Blood
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Cell Transformation, Neoplastic*
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Cells, Cultured
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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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Gene Expression Regulation
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Genes, myc*
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Genes, ras*
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Leucine Zippers*
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Methylation
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Mice
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Molecular Sequence Data
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Polymerase Chain Reaction
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Proto-Oncogene Proteins c-myc / metabolism*
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Transfection
Substances
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
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DNA-Binding Proteins
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Proto-Oncogene Proteins c-myc
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Max protein, mouse
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DNA
Associated data
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GENBANK/M63903
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GENBANK/M64376
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GENBANK/M64377
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GENBANK/M64378
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GENBANK/M64379
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GENBANK/M64380
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GENBANK/M64381
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GENBANK/M64382
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GENBANK/M64383
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GENBANK/M64384