A group II intron in the Neurospora mitochondrial coI gene: nucleotide sequence and implications for splicing and molecular evolution.

AUTOR(ES)

Field, D J

RESUMO

The temperature-sensitive Neurospora nuclear mutant cyt18-1 is deficient in splicing many Group I mitochondrial introns when grown at its non-permissive temperature; however, splicing of intron 1 in the coI gene of the Adiopodoume (formerly called North Africa) strain is unaffected (R.A. Collins and A.M. Lambowitz, J. Mol. Biol. 184: 413-428, 1985). Here we show that coI intron 1 is a typical Group II intron, the only one identified to date in Neurospora. The differential effect of the cyt18-1 mutation suggests that splicing of certain introns could be regulated independently of others by nuclear-encoded proteins. The intron contains a long open reading frame (ORF) resembling that of the Neurospora Mauriceville mitochondrial plasmid. The intron and plasmid ORFs share unusual features of codon usage that suggest both evolved outside of the Neurospora mitochondrial genetic system.

Documentos Relacionados

• A mixed group II/group III twintron in the Euglena gracilis chloroplast ribosomal protein S3 gene: evidence for intron insertion during gene evolution.
• Self-splicing of the mobile group II intron of the filamentous fungus Podospora anserina (COI I1) in vitro.
• Structure-function relationships in a self-splicing group II intron: a large part of domain II of the mitochondrial intron aI5 is not essential for self-splicing.
• Sequence requirements for branch formation in a group II self-splicing intron.
• Mitochondrial Mg2+ homeostasis is critical for group II intron splicing in vivo