Identification of a transcriptional enhancer in a mouse amyloid gene.

We have employed a mouse liver-derived cell line (BNL) to identify DNA sequences in the promoter of the serum amyloid A3 (SAA3) gene essential for expression. In both transient DNA transfection assays and BNL cells stably transformed with SAA3 fusion genes, deletion analysis of the SAA3 promoter indicates that sequences between -185 and -138 base pairs 5' to the transcription initiation site are essential for expression of heterologous genes. A 69-base pair sequence spanning this region markedly augmented expression of the bacterial chloramphenicol transacetylase gene regardless of orientation or position. The homology of this sequence with sequences in the promotors of other genes expressed by liver during inflammation suggests a common mechanism of regulation.