OBF-1, a novel B cell-specific coactivator that stimulates immunoglobulin promoter activity through association with octamer-binding proteins

Cell. 1995 Feb 10;80(3):497-506. doi: 10.1016/0092-8674(95)90500-6.


Recent biochemical and genetic studies indicate that in addition to the octamer-binding proteins Oct-1 and Oct-2, other B cell components are required for lymphoid-restricted, octamer site-mediated immunoglobulin gene promoter activity. Using a genetic screen in yeast, we have isolated B cell-derived cDNAs encoding Oct-binding factor 1 (OBF-1), a novel protein that specifically associates with Oct-1 and Oct-2. Biochemical studies demonstrate that OBF-1 has no intrinsic DNA-binding activity and recognizes the POU domains of Oct-1 and Oct-2, but not those of Oct-4 and Oct-6. The OBF-1 mRNA is expressed in a highly cell-specific manner, being most abundant in B cells and essentially absent in most of the other cells or tissues tested. Furthermore, expression of OBF-1 in HeLa cells selectively stimulates the activity of a natural immunoglobulin promoter in an octamer site-dependent manner. Thus, OBF-1 has all the properties expected for a B cell-specific transcriptional coactivator protein.

MeSH terms

  • Amino Acid Sequence
  • B-Lymphocytes
  • Cell Line
  • Cloning, Molecular
  • DNA / metabolism
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation / physiology
  • Gene Library
  • Genes, Immunoglobulin / genetics*
  • HeLa Cells
  • Host Cell Factor C1
  • Humans
  • Molecular Sequence Data
  • Octamer Transcription Factor-1
  • Octamer Transcription Factor-2
  • Organ Specificity
  • Promoter Regions, Genetic / genetics*
  • RNA, Fungal / analysis
  • RNA, Messenger / analysis
  • Sequence Analysis, DNA
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism
  • Transcription Factors / metabolism
  • Transcriptional Activation / genetics*
  • Yeasts / genetics


  • DNA-Binding Proteins
  • HCFC1 protein, human
  • Host Cell Factor C1
  • Octamer Transcription Factor-1
  • Octamer Transcription Factor-2
  • POU2AF1 protein, human
  • POU2F1 protein, human
  • POU2F2 protein, human
  • RNA, Fungal
  • RNA, Messenger
  • Trans-Activators
  • Transcription Factors
  • DNA

Associated data

  • GENBANK/Z47550
  • GENBANK/Z49194