Organization of chloroplast ribosomal RNA genes and in vitro self-splicing activity of the large subunit rRNA intron from the green alga Chlorella vulgaris C-27

We analyzed sequences of the divergent domain at the 5' end of the large subunit rRNA gene from the mitosporic entomopathogenic fungi Paecilomyces sp., Paecilomyces fumosoroseus, Paecilomyces farinosus, Paecilomyces lilacinus, Verticillium lecanii, Verticillium psalliotae, Beauveria bassiana, Aschersonia sp., Aschersonia placenta, ascomycetous Cordyceps sp., and Cordyceps militaris. Phylogenetic analysis showed P. fumosorseus as the best characterized out of the analyzed species with the B. bassiana clade as its sister group. Two of the P. farinosus isolates were invariably placed within the Verticillium cluster, which also contained C. militaris. The only analyzed P. lilacinus isolate appeared on the root of the hyphomycetous fungi and was characterized as the most distinct from all the hyphomycetous fungi tested. Polyphyly of the genus Paecilomyces was well supported by the Kishino-Hasegawa test. In all trees based on the small subunit rRNA gene sequences obtained from the GenBank(tm), V. lecanii, V. psalliotae, P. fumosoroseus, P. tenuipes and B. bassiana form, together with that of C. militaris, the best supported cluster in the tree. The rest of Cordyceps spp. constitute a distinct clade. Phylogenetic relationships derived from both tested DNA regions show polyphyly of the genus Paecilomyces and close relationships among entomopathogenic species of the genera Verticillium, Paecilomyces, and Beauveria.Key words: Paecilomyces, Verticillium, Beauveria, Aschersonia, entomopathogenic fungi, molecular phylogeny, ribosomal RNA genes.

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Sequence heterogeneity in the duplicate large subunit ribosomal RNA genes of Tetrahymena pyriformis mitochondrial DNA.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)45710-9 ◽

1990 ◽

Vol 265 (36) ◽

pp. 22336-22341

Author(s):

T Y Heinonen ◽

M N Schnare ◽

M W Gray

Keyword(s):

Mitochondrial Dna ◽

Ribosomal Rna ◽

Large Subunit ◽

Tetrahymena Pyriformis ◽

Ribosomal Rna Genes ◽

Sequence Heterogeneity ◽

Rna Genes ◽

Large Subunit Ribosomal Rna

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Study of the function of Escherichia coli ribosomal RNA through site-directed mutagenesis

Biochemistry and Cell Biology ◽

10.1139/o90-023 ◽

1990 ◽

Vol 68 (1) ◽

pp. 169-179 ◽

Cited By ~ 6

Author(s):

Daniel Leclerc ◽

Léa Brakier-Gingras

Keyword(s):

Escherichia Coli ◽

Ribosomal Rna ◽

Ribosomal Proteins ◽

Large Body ◽

Ribosomal Rna Genes ◽

16S Ribosomal Rna ◽

Site Directed Mutagenesis ◽

Directed Mutagenesis ◽

Rna Genes

Various approaches have been developed to study how mutations in Escherichia coli ribosomal RNA affect the function of the ribosome. Most of them are in vivo approaches, where mutations are introduced in a specialized plasmid harboring the ribosomal RNA genes. The mutated plasmids are then expressed in an appropriate host, where they can confer resistance to antibiotics whose target is the ribosome. Conditions can be used where the host ribosomal RNA genes or the host ribosomes are selectively inactivated, and the effect of the mutations on ribosome assembly and function can be studied. Another approach, which has been developed mainly with 16S ribosomal RNA, can be used entirely in vitro. In this approach, a plasmid has been constructed which contains the 16S ribosomal RNA gene under control of a T7 promoter. Mutations can be introduced in the 16S ribosomal RNA sequence and the mutated 16S ribosomal RNAs are produced by in vitro transcription. It is then possible to investigate how the mutations affect the assembly of the 16S ribosomal RNA into 30S subunits and the activity of the reconstituted 30S subunits in cell-free protein synthesis assays. Although these approaches are recent, they have already provided a large body of interesting information, relating specific RNA sequences to interactions with ribosomal proteins, to ribosome function, and to its response to antibiotics.Key words: ribosomal RNA, ribosome, site-directed mutagenesis, antibiotic resistance.

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