Mxi1, a protein that specifically interacts with Max to bind Myc-Max recognition sites.
We used the interaction trap to isolate a novel human protein that specifically interacts with Max. This protein, Mxi1 (for Max interactor 1), contains a bHLH-Zip motif that is similar to that found in Myc family proteins. Mxi1 interacts specifically with Max to form heterodimers that efficiently bind to the Myc-Max consensus recognition site. When bound to DNA by a LexA moiety in yeast, Mxi1 does not stimulate transcription. mxi1 mRNA is expressed in many tissues, and its expression is elevated in U-937 myeloid leukemia cells that have been stimulated to differentiate. These facts are consistent with a model in which Mxi1-Max heterodimers indirectly inhibit Myc function in two ways: first, by sequestering Max, thus preventing the formation of Myc-Max heterodimers, and second, by competing with Myc-Max heterodimers for binding to target sites.
Zervos
A S
AS
Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114.
Gyuris
J
J
Brent
R
R
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D002454:Cell Differentiation / Q000502:physiology; D003001:Cloning, Molecular; D004273:DNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D015723:Gene Library; D016259:Genes, myc; D006367:HeLa Cells; D006801:Humans; D016350:Leucine Zippers / Q000235:genetics / Q000502:physiology*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016366:Open Reading Frames; D010957:Plasmids; D017433:Protein Structure, Secondary; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases; D014157:Transcription Factors; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins; D001616:beta-Galactosidase / Q000378:metabolism; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012697:Serine Endopeptidases; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D001616:beta-Galactosidase; D000099160:LexA Repressor Protein; C499330:MAX protein, human; C079440:MXI1 protein, human; C067850:Myc associated factor X