Organization of the 18S, 5S, 4S rRNA genes and the tRNA-like repeat in the mitochondrial genomes of three lupin species

Southern blots of mitochondrial (mt) DNAs of three ''Lupinus'' species cleaved with three restriction enzymes were probed with ''Lupinus luteus'' mtDNA fragments containing 18S, 5S, rRNA genes or a tRNA-like repeat. Comparison of the number of hybridizing bands and their intensity suggested that the mt 18S and 5S rRNA genes occur mostly in one copy in the genomes of three lupin species. The exception concerned the ''Lupinus angustifolius'' 5S rRNA gene showing two hybridizing bands of unequal intensity. The results of hybridization of the lupin mitochondrial genomes with a probe specific for the ''Lupinus luteus'' tRNA-like repeat pointed to the presence of such a repeat in other parts of the genomes besides the vicinity of the 18S rRNA gene. Northern hybridization analysis showed the presence of 18S, 5S and tRNA-like repeat transcripts similar in size in all lupin species. (author). 23 refs, 4 figs