A member of the C/EBP family, NF-IL6 beta, forms a heterodimer and transcriptionally synergizes with NF-IL6.
Using a DNA probe from the DNA-binding portion of the NF-IL6 gene and an antibody against the DNA-binding domain of NF-IL6, we isolated a gene homologous to NF-IL6 in the DNA-binding and leucine zipper domains. This intronless gene, termed NF-IL6 beta encodes a 269-amino acid protein with a potential leucine zipper structure, and the gene product can bind to the CCAAT homology as well as the viral enhancer core sequence, as in the cases of NF-IL6 and C/EBP. This gene is expressed at an undetectable or a minor level in normal tissues but is induced by lipopolysaccharide or inflammatory cytokines, as in the case of NF-IL6. NF-IL6 beta easily forms a heterodimer with NF-IL6 in vitro and the heterodimeric complex binds to the same DNA sequence as the respective homodimers. When examined by transient luciferase assays, NF-IL6 beta is consistently a stronger transactivator than NF-IL6. Furthermore, NF-IL6 beta shows a synergistic transcriptional effect with NF-IL6. These data suggest that NF-IL6 beta is an important transcriptional activator in addition to NF-IL6 in regulation of the genes involved in the immune and inflammatory responses.
Kinoshita
S
S
Institute for Molecular and Cellular Biology, Osaka University, Japan.
Akira
S
S
Kishimoto
T
T
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D022762:CCAAT-Enhancer-Binding Proteins; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000502:physiology*; D015870:Gene Expression; D005786:Gene Expression Regulation; D006801:Humans; D066298:In Vitro Techniques; D015850:Interleukin-6 / Q000235:genetics*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D005810:Multigene Family; D009687:Nuclear Proteins / Q000235:genetics* / Q000502:physiology; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D015850:Interleukin-6; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D014157:Transcription Factors