Functional prokaryotic gene control signals within a eukaryotic rainbow trout protamine promoter

Following the construction of a series of pSV2-cat derived plasmids containing the chloramphenicol acetyltransferase (CAT) gene under the control of a eukaryotic trout protamine promoter, it was noted that Escherichia coli, transformed with these plasmids, developed resistance to chloramphenicol (CM). This result suggested that the eukaryotic trout protamine promoter possessed significant prokaryotic promoter activity. Modification of the trout protamine promoter region by removing the region containing the eukaryotic Goldberg-Hogness box in the plasmid p525-cat increased the expression of the CAT gene almost to the wild-type level and conferred strong CM resistance. Sequence comparisons of the plasmid series indicate that prokaryotic promoter elements are present in the trout protamine promoter and that their similarity to the prokaryotic promoter consensus sequences and the distance between the two elements is more favourable in p525-cat, the plasmid which confers the greatest CM resistance.