PRESENCE OF A TRANSPOSON-LIKE ELEMENT IN THE PROMOTER REGION OF AN INACTIVE PATATIN GENE IN SOLANUM-TUBEROSUM-L

The promoter of the PGT3 patatin gene belonging to the class II subfamily is highly homologous to other class II patatin genes except for a 736 bp insertion in front of the putative transcription start site. The insertion is characterized by structural features resembling a transposable element such as an 11 bp inverted repeat at the termini and an 8 bp duplication flanking the insertion site. Despite the high homology to active patatin genes, fusion of its promoter to the β-glucuronidase reporter gene does not lead to detectable β-glucuronidase (GUS) activity in transgenic potato or tobacco plants, suggesting that the inactivation of this gene might be caused by the insertion of the transposon like element. © 1990 Kluwer Academic Publishers.