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 vitro transcription/translation we show that the basal transcription factor NF-Y or a related factor binds to the cAMP-responsive inverted CCAAT box recently identified in the rat fatty acid synthase (FAS) gene from 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 FAS and tryptophan hydroxylase. Since NF-Y is a constitutively produced factor, not surprisingly, no differences in 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 implies that NF-Y might be modified in response to cAMP or might interact with another factor whose properties are altered by cAMP.