A Jun-binding protein related to a putative tumor suppressor.
A lambda gt11 cDNA library of chicken embryo fibroblasts was screened with biotinylated Jun protein to identify Jun-binding clones. Eight such clones were isolated; one contains a gene referred to as jif-1 that is homologous to the putative tumor suppressor gene QM. jif-1 codes for a protein of 25 kDa that binds to the leucine zipper of viral and cellular Jun. The Jif-1 protein also binds to itself. Jif-1 does not contain a leucine zipper, and it does not bind to the 12-O-tetradecanoylphorbol 13-acetate response element DNA sequence. Complex formation of Jif-1 with Jun inhibits DNA binding and reduces transactivation by Jun. Addition of Fos protein to Jun-Jif-1 complexes restores DNA-binding activity. These observations suggest that Jif-1 is a negative regulator of Jun.
Monteclaro
F S
FS
Department of Microbiology, University of Southern California School of Medicine, Los Angeles.
Vogt
P K
PK
D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002642:Chick Embryo; D005347:Fibroblasts; D015723:Gene Library; D016147:Genes, Tumor Suppressor / Q000235:genetics*; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid; D000080882:Ribosomal Protein L10; D012269:Ribosomal Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015533:Transcriptional Activation; D025521:Tumor Suppressor Proteins
D030161:Avian Proteins; D002352:Carrier Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012269:Ribosomal Proteins; D025521:Tumor Suppressor Proteins; C082381:jif-1 protein, chicken