[The features of the 3' terminal sequences of the 18S rRNA gene from silkworm Attacus ricini].

The 3' terminal sequence of the gene for 18S rRNA of silkworm Attacus ricini have been sequenced. Comparison of this sequence with the 18S rDNA of silkworm Bombyx mori, Drosophila melanogaster, rat and the 16S rDNA of E. coli has shown that there is a remarkable homology between them. Moreover, the stem and loop formation of 3' regions of these rDNAs are very similar. There is a conservative EcoR1 site in the 3' region of these rDNAs. These results may contribute to the understanding of the functions of the 3' end of 18S rDNA in protein synthesis, in proceeding of rRNA precursor, and to the understanding of the evolutionary relation of rDNAs.