Sequence comparison of the rDNA introns from six different species of Tetrahymena.
AUTOR(ES)
Nielsen, H
RESUMO
We have studied the sequence variation of the rDNA intron among six species of Tetrahymena. From these data, the intron appears to be relatively well conserved in evolution. We have evaluated the sequence variations among the most distant of these species in relation to the secondary structure model for the intron RNA of Cech et al. (Proc. Natl. Acad. Sci. U.S.A. 80, 3903 (83)). Most of the sequence variation in the four new sequences reported here is found in single stranded loops in the model. However, in four cases we found nucleotide substitutions in duplex stem regions, two of them involving compensating base pair changes. Interestingly, one of these is found in a region that is known to be dispensable in the in vitro splicing reaction suggesting differences between the in vivo and in vitro reactions. One of the single nucleotide deletions is found in the so-called "internal guide sequence" which has been implicated in the alignment process during splicing. In conclusion, none of the observed natural sequence variations are in disfavor of the proposed secondary structure model.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=322054Documentos Relacionados
- Strong sequence conservation of a 38 bp region near the center of the extrachromosomal rDNA palindrome in different Tetrahymena species.
- Complete sequence of the extrachromosomal rDNA molecule from the ciliate Tetrahymena thermophila strain B1868VII.
- Nucleotide sequence of the 18S rDNA from the microalga Nanochlorum eucaryotum.
- The rDNA of C. elegans: sequence and structure.
- Localization of putative transcription initiation site on the cloned rDNA fragment of Tetrahymena pyriformis.