NF-Y BINDS TO THE INVERTED CCAAT BOX, AN ESSENTIAL ELEMENT FOR CAMP-DEPENDENT REGULATION OF THE RAT FATTY-ACID SYNTHASE (FAS) GENE

Using EMSA competition experiments together with supershifts and in vi tro transcription/translation we show that the basal transcription fac tor NF-Y or a related factor binds to the cAMP-responsive inverted CCA AT box recently identified in the rat fatty acid synthase (FAS) gene f rom nucleotide -99 to -92 relative to the transcription start site of the FAS mRNA. This result indicates a putative novel role for NF-Y in the cAMP-dependent gene regulation in a small class of genes such as F AS and tryptophan hydroxylase. Since NF-Y is a constitutively produced factor, not surprisingly, no differences ill the specific DNA/protein complex with the CCAAT(FAS) box and nuclear proteins from H4IIE cells treated with cAMP and/or insulin or not could be observed. This impli es that NF-Y might be modified in response to cAMP or might interact w ith another factor whose properties are altered by cAMP.