High impact information on 15S rRNA

• In yeast cells, mutant alleles of MSS1, encoding a mitochondrial GTP-binding protein, manifest a respiratory-deficient phenotype only when coupled with mitochondrial 15S rRNA P(R)(454) mutation corresponding to human A1555G mutation [1].
• PET123 appears to be present at levels comparable to those of other mitochondrial ribosomal proteins, and its accumulation is dependent on the presence of the 15S rRNA gene in mitochondria [2].
• We have determined the nucleotide sequence alteration in the 15S rRNA gene of a Saccharomyces cerevisiae strain carrying the previously described mitochondrial ochre suppressor, MSUI [3].
• Nature of an inserted sequence in the mitochondrial gene coding for the 15S ribosomal RNA of yeast [4].
• This enabled us to identify where in the determined DNA sequence the 21S ribosomal RNA and the precursor for 15S ribosomal RNA (15.5S rRNA) start, since both transcripts are initiated de novo (Levens et al. (1981) J.Biol.Chem., 256, 5226-5232) [5].

Biological context of 15S rRNA

• The sequence analysis of the four mutant mna6 alleles revealed that Leu(109) --> Phe, Arg(111) --> Lys, Pro(424) --> Leu, or Pro(438) --> Leu amino acid substitution in Mna6p causes temperature-dependent loss of the 15S rRNA [6].
• Four different mutant alleles of a nuclear gene (MNA6), which lose mt 15S rRNA at nonpermissive temperature (36 degrees C), were previously generated by EMS mutagenesis of Saccharomyces cerevisiae [6].
• The mitochondrial genome of S. cerevisiae encodes two components of the small ribosomal subunit, 15S rRNA and the Var1 protein, both of which are necessary for the formation of mature 37S subunits [7].
• Both 15S ribosomal RNA and 15.5S RNA are fully localised within a 2000 base pair HapII fragment [8].

Anatomical context of 15S rRNA

• It is concluded that the parl-r mutation in strain 4810P affects a component of the mitochondrial ribosome, possibly by altering the 15S rRNA or a protein of the small ribosomal subunit [9].

References