ISSN:
1432-0983
Keywords:
Podospora mitochondrial DNA
;
Senescence-associated plasmid
;
Intron secondary structure
;
Intronic reading frames
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Recently, the nucleotide sequences for three “mitochondrial plasmids” associated with senescence of Podospora anserina were determined (Cummings et al. 1985). One of these sequences, corresponding to the plasmid termed ε senDNA, contains three class I introns, all within a protein coding sequence equivalent to the mammalian “URF1” gene. Here, we present primary and secondary structure analyses for two of these introns as well as a partial analysis for the third, which extends beyond the DNA sequence determined. With regard to both primary and secondary structure, the closest known relative of intron 1 is the self-splicing intron in the large ribosomal RNA gene of Tetrahymena. One secondary structure domain at the periphery of intron 1 and Tetrahymena models is also present in intron 2. The latter intron is the longest known class I member and contains remnants of two protein-coding sequences, one of which is split by the other. Evolutionary processes that might be responsible for the unusual structure of introns 1 and 2 are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00418495
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