Nucleotide sequence and intron structure of the apocytochrome b gene of Neurospora crassa mitochondria.

AUTOR(ES)

Helmer-Citterich, M

RESUMO

The sequence of the apocytochrome b (cob) gene of Neurospora crassa has been determined. The structural gene is interrupted by two intervening sequences of approximately 1260 bp each. The polypeptide encoded by the exons shows extensive homology with the cob proteins of Aspergillus nidulans and Saccharomyces cerevisiae (79% and 60%, respectively). The two introns are, however, located at sites different from those of introns in the cob genes of A. nidulans and S. cerevisiae (which contain highly homologous introns at the same site within the gene). The introns share several short regions of sequence homology (10-12 bp long) with each other and with other fungal mitochondrial introns. Moreover, the second intron contains a 50 nucleotide long sequence that is highly homologous with sequences within every ribosomal intron of fungal mitochondria sequenced to date. The conserved sequences may allow the formation of a core secondary structure, which is nearly identical in many mitochondrial introns. The conserved secondary structure may be required for intron splicing. The second intron contains an open reading frame, continuous with the preceding exon, of approximately 290 codons. Two stretches of 10 amino acid residues, conserved in many introns, are present in the open reading frame.

Documentos Relacionados

• Nucleotide sequence of the exons of the large subunit rRNA of Neurospora crassa mitochondria.
• Immunological identification of the alternative oxidase of Neurospora crassa mitochondria.
• Enzymes of deoxythymidine triphosphate biosynthesis in Neurospora crassa mitochondria.
• Amino acid sequence requirements for the association of apocytochrome c with mitochondria.
• Suppressor mutations identify box9 as a central nucleotide sequence in the highly ordered structure of intron RNA in yeast mitochondria.