Identification of two polypeptide segments of CCAAT/enhancer-binding protein required for transcriptipnal activation of the serum albumin gene

Alan D. Friedman, Steven L. McKnight

Research output: Contribution to journalArticle

119 Scopus citations


We used molecular genetic methods to generate systematically altered forms of CCAAT/enhancer-binding protein (C/EBP). The aim of our experiments was to identify regions of C/EBP that contribute to its capacity to activate transcription from the promoter of the serum albumin gene in cultured hepatoma cells. Earlier experiments had shown that the DNA-binding domain must remain intact for C/EBP to activate albumin transcription. We now provide evidence of two additional elements of C/EBP that are required for its geneactivating role. One such element occurs within a 28-residue region located close to the amino terminus of the protein. The other maps to a broader, more internal region of the protein and appears to exhibit functional redundancy. These newly defined elements of C/EBP exhibit two characteristics of "activation" domains delineated in studies of other gene regulatory proteins. First, they play no obvious role in the capacity of C/EBP to bind to its DNA substrate. Second, they retain function after being appended onto the DNA-binding domain of a different protein. Neither of these putative activating elements is characterized by overt distinction in either charge or preponderance of any particular amino acid. The more amino-terminal element does, however, exhibit several features suggesting that it may assume an α-helical structure. These studies offer observations and reagents that will be valuable for future studies concerning the physiologic function of C/EBP.

Original languageEnglish (US)
Pages (from-to)1416-1426
Number of pages11
JournalGenes and Development
Issue number8
StatePublished - Jan 1 1990



  • Activation
  • C/EBP
  • Serum albumin gene
  • Transcription

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology

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