RNA Structure from A to Z

RNA performs a wide variety of known functions in biological systems, and it probably is involved in an even greater variety of as yet unknown functions. It is the genome in RNA viruses, virusoids, and viroids; in viroids, it sometimes catalyzes its own specific cleavage (Hutchins et al. 1986; Prody et al. 1986). The design and construction of proteins are controlled by messenger RNAs, ribosomal RNAs, and transfer RNAs. These RNAs are formed from their primary transcripts by a processing that can involve RNA enzymes (Cech and Bass 1986) and small nuclear RNAs (Black et al. 1985). Catalytic RNAs (ribozymes) have been shown to operate on polynucleotides (Zaug and Cech 1986) and polysaccharides (Shvedova et al. 1987). Intrinsic RNA components are involved in the signal-recognition particle, which mediates the extrusion of proteins through cell membranes (Zweib and Ullu 1986). RNA also plays important roles in control of replication (Dooley et...