Primary and secondary structure of the 18 S ribosomal RNA of the insect species Tenebrio molitor

Abstract

The sequence of the 18 S rRNA of Tenebrio molitor is reported. A detailed secondary structure model for eukaryotic small subunit rRNAs is proposed. The model comprises 48 universal helices that eukaryotic and prokaryotie small subunit rRNAs have in common, plus a number of helices in areas of variable secondary structure. For the central area of the model, an alternative structure is possible, applicable only to eukaryotic small subunit rRNAs. Possibly, small subunit rRNA switched to this alternative conformation after the eukaryotic branch had been established in evolution. Another possibility is that the two conformers represent a dynamic structural switch functioning during the translational activity of the eukaryotic ribosome.small ribosomal subunit RNA; 18 S rRNA; Nucleotide sequence; Secondary structure; (Tenebrio molitor)

18S rRNA Secondary Structure and Phylogenetic Position of Peloridiidae (Insecta, Hemiptera)

“…Only the final hairpin tetraloop UAAC and 4 pairings in the stem could be constructed in common. (19) The retained structure is the same as that predicted for the basal portion of helix 19 of T. molitor (Hendriks et al, 1988b). (20) The retention of this pseudoknot has been experimentally confirmed .…”

“…In the peloridiid model this G is at base position 54 and the C is at position 86. If mfold is constrained to predict the structure with this G ⅐ C pair at the base of this helix, the obtained structure for the peloridiid differs from the structure of helix 6 predicted for T. molitor (Hendriks et al, 1988b), but our configuration for this helix shows greater stability (Ϸ3.7 kcal/mol; less free-energy than in the T. molitor model) because of a greater number of G ⅐ C pairs. (7) molitor by U ⅐ G in the peloridiids.…”

“…(10) This helix comprises one of the more variable regions of eukaryotic 18S rRNA. The structure proposed for T. molitor by Hendriks et al (1988b) cannot be reconstructed using the peloridiid sequences. Only the thermodynamic approach is available to infer secondary structure until there are more insect sequences to take into consideration.…”

“…(Hendriks et al, 1988a); CrustaceaArtemia salina (Nelles et al, 1984); Insecta: Coleoptera-Tenebrio molitor (Hendriks et al, 1988b); Hemiptera-Acyrthosiphon pisum (Kwon et al, 1991); Diptera-Drosophila melanogaster (Hancock et al, 1988;Gutell, 1994;van de Peer et al, 2000).…”

A Molecular Phylogeny of the Tiger Beetles (Cicindelidae): Congruence of Mitochondrial and Nuclear rDNA Data Sets

“…This part of the sequence lacks any obvious similarity with the carabid outgroups (Fig. 2) or with published sequences of other beetles including tenebrionids (Hendriks et al, 1988) and weevils (Cano et al, 1993). Secondary structure predictions of this region indicate that the unique sequence forms a single stem-loop structure which is initiated at two adjacent G-C pairings (one of them a G-U pairing in some taxa).…”