Alteration in the processing of ribosomal ribonucleic acid inSaccharomyces cerevisiae caused by ethidium bromide

1979 ◽  
Vol 3 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Liliana W. Waltschewa
Keyword(s):  
Ethidium Bromide ◽  
Ribonucleic Acid ◽  
Ribosomal Ribonucleic Acid

scholarly journals Identical 3′-terminal octanucleotide sequence in 18S ribosomal ribonucleic acid from different eukaryotes. A proposed role for this sequence in the recognition of terminator codons

1974 ◽  
Vol 141 (3) ◽  
pp. 609-615 ◽  
Author(s):  
John Shine ◽  
Lynn Dalgarno
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
18S Rrna ◽  
Base Sequence ◽  
Terminal Sequence ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species

The 3′-terminal sequence of 18S ribosomal RNA from Drosophila melanogaster and Saccharomyces cerevisiae was determined by stepwise degradation from the 3′-terminus and labelling with [3H]isoniazid. The sequence G-A-U-C-A-U-U-AOH was found at the 3′-terminus of both 18S rRNA species. Less extensive data for 18S RNA from a number of other eukaryotes are consistent with the same 3′-terminal sequence, and an identical sequence has previously been reported for the 3′-end of rabbit reticulocyte 18S rRNA (Hunt, 1970). These results suggest that the base sequence in this region is strongly conserved and may be identical in all eukaryotes. As the 3′-terminal hexanucleotide is complementary to eukaryotic terminator codons we discuss the possibility that the 3′-end of 18S rRNA may have a direct base-pairing role in the termination of protein synthesis.

The ribosomes of Plasmodium berghei: isolation and ribosomal ribonucleic acid analysis

Parasitology ◽  
1978 ◽  
Vol 77 (3) ◽  
pp. 345-366 ◽  
Author(s):  
F. W. Miller ◽  
Judith Ilan
Keyword(s):  
Plasmodium Berghei ◽  
Ribonucleic Acid ◽  
Ribosomal Subunit ◽  
High Yield ◽  
Small Component ◽  
40S Ribosomal Subunit ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Specific Degradation ◽  
Triton X

SummaryRibosomes and high molecular weight ribosomal ribonucleic acid (rRNA) from the blood stages of Plasmodium berghei parasites were studied in preparations free from host ribosome contamination. Purified malarial ribosomes were isolated in high yield from a population of ultrastructurally intact, viable parasites by hypertonic lysis with Triton X-100 and differential centrifugation. These ribosomes were shown to be derived from active polysomes and could be dissociated into subunits by puromycin–0·5 m KCl treatment. Malarial rRNA extracted from purified 40S and 60S ribosomal subunits was characterized by electrophoretic, sedimentation and base ratio analyses. Like certain other protozoa, the P. berghei 40S ribosomal subunit possessed an exceptionally large RNA species (mol. wt 0·9 × 106), while RNA isolated from the parasite's 60S subunit (mol. wt 1·5 × 106) was specifically ‘nicked’ to produce one large component (mol.wt 1·2 × 106) and one small component (mol.wt 0·3 × 106) in equimolar quantities. These rRNA's migrate identically on polyacrylamide gels after heating to 63°C for 5 mm or under denaturing conditions in the presence of formamide, indicating an absence of aggregation and non-specific degradation of the rRNA species. Base composition studies showed P. berghei rRNA to be low in guanosine and cytosine content, as is the case for protozoa generally.

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