FIGURE 3.

(A) Nucleotide sequence of the mim3-1 region in the 15S rRNA. The nucleotide sequence of 629-754 region in the mitochondrial 15S rRNA of various strains is shown. Sequences are from: 1-[50]; 2: [51]; 3: [17]; 4 and 5: [11]. The position 633 is the only one mutated in the ochre suppressors MSU1 and mim3-1. The underlined bases are engaged in a stem structure.

(B) Position of mim3-1 on the 530 stem-loop secondary structure. On the right the structure of yeast mitochondrial 15s rRNA is shown which is homologous to the 530 bacterial one, numbered from 5′. The G633 which is replaced by C in mim3-1 and by A in MSU1 suppressors [11] is boxed. On the left the 530 stem-loop structure of the 15S rRNA in Eubacteria is shown with numbering according to E.coli. The substitution of G530 (circled) by either C, A or U is lethal in E.coli [28]. Note that the boxed triplet in both structures is complementary and may interact in the tertiary structure according to [22, 23].

11. Shen Z, Fox TD (1989) Substitution of an invariant nucleotide at the base of the highly conserved 530-loop’ of 15S rRNA causes suppression of yeast mitochondrial ochre mutations. Nucl Acids Res 17: 4535-4539. http://dx.doi.org/10.1093/nar/17.12.4535

17. Hüttenhofer A, Sakai H, Weiss-Brummer B (1988) Site-specific AT-cluster insertions in the mitochondrial 15s rRNA gene of the yeast S.cerevisiae. Nucl Acids Res 16: 8665-8674. http://dx.doi.org/10.1093/nar/16.17.8665

22. Powers T, Noller HF (1991) A functional pseudoknot in 16S ribosomal RNA.
EMBO J 10: 2203-2214. http://www.ncbi.nlm.nih.gov/pubmed/?term=1712293

23. Woese CR, Gutell RR (1989) Evidence for several higher order structural elements in ribosomal RNA. Proc Natl Acad Sci U S A 86: 3119-3122. http://www.ncbi.nlm.nih.gov/pubmed/?term=2654936

28. Powers T, Noller HF (1990) Dominant lethal mutations in a conserved loop in 16s rRNA. Proc Natl Acad Sci USA 87: 1042-046. http://dx.doi.org/10.1073/pnas.87.3.1042

50. Sor F, Fukuhara H (1982) Séquence nucléotidique du gène de l’ARN ribosomique 15S mitochondrial de la levure. C R Acad Sci Paris 291: 933-936. http://www.ncbi.nlm.nih.gov/pubmed/?term=6261980

51. Li M, Tzagoloff A, Underbrink-Lyon K, Martin NC (1982) Identification of the paromomycin resistance mutation in the 15S rRNA gene in yeast mitochondria. J Biol Chem 257: 592-5928. http://www.ncbi.nlm.nih.gov/pubmed/?term=6279619