The basic region of AP-1 specifies glucocorticoid receptor activity at a composite response element.

  1. J N Miner and
  2. K R Yamamoto
  1. Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448.

Abstract

Unrelated factors collaborate at composite response elements to confer novel patterns of transcriptional regulation. For example, AP-1 and glucocorticoid receptor bind and mutually affect their activities at a 25-bp composite element, plfG. We found that different members of the AP-1 factor family that behave similarly in the absence of receptor are strikingly distinct in its presence: They specify opposite (enhancement vs. repression) regulatory actions by the receptor. Four amino acids within the AP-1 DNA-binding domain were identified as crucial determinants of receptor regulatory activity at plfG. We conclude that interactions of factors from separate transcription factor families at composite response elements provide a mechanism by which a single factor can regulate both positively or negatively, and a potential resolution of the apparent functional redundancy within regulatory factor families.

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