A functional eukaryotic promoter is contained within the first intron of the hGH-N coding region

Human growth hormone is frequently used as a reporter gene in studies addressing the regulation of eukaryotic promoters. Here we present evidence that the first intron of the hGH-N coding region contains a novel eukaryotic promoter which is able to direct the expression of hGH-N and luciferase reporter genes. The corresponding transcriptional initiation site is located downstream of the splice acceptor site of exon 2. This internal hGH-N promoter can interfere with the transcriptional control elements of a promoter linked to the hGH-N coding region and thereby complicate the interpretation of data obtained with hGH-N as a reporter gene.