IN-VIVO ANALYSIS OF PLANT 18-S RIBOSOMAL-RNA STRUCTURE

This chapter discusses in vivo analysis of plant 18 S ribosomal RNA structure. The ribosomal RNAs (rRNAs) are involved in multiple molecular interactions with both protein factors and other RNAs in addition to having an extensive intramolecular secondary structure of their own. These interactions involve not only particular sequence domains but also recognition of secondary and tertiary structural features of the RNA molecule. DNA, RNA, and protein sequence comparisons are used to infer the phylogenetic relationships and time of divergence of a variety of species. The small subunit ribosomal RNA is most useful in these studies, allowing wide-ranging comparisons at the species level even among eukaryotic and prokaryotic kingdoms. However, for ribosomal RNA, evolutionary differences may be more directly reflected in alteration or conservation of specific structures than in general RNA sequence changes. © 1993