title: Evidence for interaction of 5.8S rRNA with the 5'- and 3'- terminal segments of Saccharomyces cerevisiae 25S rRNA.
abstract: The possible sites of 5.8S:25S rRNA interaction in Saccharomyces cerevisiae are investigated by blot-hybridization of in vivo 32P-labelled 5.8S rRNA with restriction fragments from the 25S rRNA gene. Strong hybridization signals are obtained with fragments from the 5'-end (nucleotides 1 to 494) and the 3'-end (3066 to 3391) of the gene. The fragments from the remaining part of the gene are negative. A computer analysis of the known Saccharomyces cerevisiae 5.8S (Rubin 1973) and 25S (Georgiev et al. 1981) rRNA sequences show a markedly higher complementarity between 5.8S rRNA and the 5'- and 3'-terminal segments of 25S rRNA corresponding to the hybridization positive rDNA fragments. In accordance with the experimental and sequence analysis data, two alternative end-to-end base pairing models of possible 5.8S:25S rRNA binding are proposed. Both models imply that 5.8S rRNA connects the 5'- and 3'-terminal segments of 25S rRNA, but differ in the extent of preservation of the secondary structure typical of free 5.8S rRNA. It is suggested that the requirement for 5'- and 3'-end binding of 23S rRNA in Escherichia coli is conserved in evolution and that in eukaryotes 5.8S rRNA plays the role of joining together the two ends of L-rRNA molecules.
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D004271:DNA, Fungal / Q000378:metabolism; D004275:DNA, Ribosomal; D005800:Genes, Fungal; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D012331:RNA, Fungal / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D012331:RNA, Fungal; D012335:RNA, Ribosomal; D004247:DNA