Cloning and characterization of ribosomal RNA gene of Physarum polycephalum

As a first step in studies on the structure and expression of rRNA gene of Physarum polycephalum, the cloning of the gene in Escherichia coli with plasmid vector DNAs was performed and 8 different kinds of clones containing 26S, 19S, and 5.85 rRNA genes were obtained. Using these cloned fragments, the location of these rRNA genes was determined by the Southern hybridization and S1 mapping method. Cloning of rDNA fragments made it possible to analyze the fine structure of the rDNA.