Three variant introns of the same general class in the mitochondrial gene for cytochrome oxidase subunit 1 in Aspergillus nidulans.
AUTOR(ES)
Waring, R B
RESUMO
The oxiA gene of Aspergillus nidulans, coding for cytochrome oxidase subunit 1, is shown by DNA sequencing to contain three introns. An AUG start codon is not present at the beginning of the sequence, suggesting that either another codon, possibly the four base codon AUGA, is used for initiation or there is a further short intron between the true start codon and the beginning of the recognisable coding region. The second and third introns have long open reading frames, which could code for maturase proteins. The lack of conservation of amino acid sequence in the putative region of proteolytic cleavage for maturase formation suggests that the first conserved decapeptide may act as the recognition signal for protein processing. The third intron is remarkably (70%) homologous to the second intron of the cytochrome oxidase subunit 1 gene of Schizosaccharomyces pombe and both are located in exactly the same position. The third Aspergillus intron has an in-frame insertion of a 37-bp GC-rich DNA sequence which is now flanked by a 5-bp repeat, a well-known feature of transposable elements. All three introns in the oxiA gene have a 'core' RNA secondary structure found in a class of introns fitting the RNA splicing model of Davies et al. (1982). This core RNA structure may play a catalytic as well as a structural role in intron splicing. A sequence within the intron could act as a guide to align the splice sites of two of the introns in accordance with the model of Davies et al.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=557652Documentos Relacionados
- The mitochondrial genome of the fission yeast Schizosaccharomyces pombe: highly homologous introns are inserted at the same position of the otherwise less conserved cox1 genes in Schizosaccharomyces pombe and Aspergillus nidulans.
- Sequence of the rice mitochondrial gene for cytochrome oxidase subunit 3.
- Group I introns in the liverwort mitochondrial genome: the gene coding for subunit 1 of cytochrome oxidase shares five intron positions with its fungal counterparts.
- Internal structure of a mitochondrial intron of Aspergillus nidulans.
- Proton pump coupled to cytochrome c oxidase in the cyanobacterium Anacystis nidulans.