Transcription-dependent DNA transactions in the mitochondrial genome of a yeast hypersuppressive petite mutant.
Mol Cell Biol
; 18(5): 2976-85, 1998 May.
Article
en En
| MEDLINE
| ID: mdl-9566917
ABSTRACT
Mitochondrial DNA (mtDNA) of Saccharomyces cerevisiae contains highly conserved sequences, called rep/ori, that are associated with several aspects of its metabolism. These rep/ori sequences confer the transmission advantage exhibited by a class of deletion mutants called hypersuppressive petite mutants. In addition, because they share features with the mitochondrial leading-strand DNA replication origin of mammals, rep/ori sequences have also been proposed to participate in mtDNA replication initiation. Like the mammalian origins, where transcription is used as a priming mechanism for DNA synthesis, yeast rep/ori sequences contain an active promoter. Although transcription is required for maintenance of wild-type mtDNA in yeast, the role of the rep/ori promoter as a cis-acting element involved in the replication of wild-type mtDNA is unclear, since mitochondrial deletion mutants need neither transcription nor a rep/ori sequence to maintain their genome. Similarly, transcription from the rep/ori promoter does not seem to be necessary for biased inheritance of mtDNA. As a step to elucidate the function of the rep/ori promoter, we have attempted to detect transcription-dependent DNA transactions in the mtDNA of a hypersuppressive petite mutant. We have examined the mtDNA of the well-characterized petite mutant a-1/1R/Z1, whose repeat unit shelters the rep/ori sequence ori1, in strains carrying either wild-type or null alleles of the nuclear genes encoding the mitochondrial transcription apparatus. Complex DNA transactions were detected that take place around GC-cluster C, an evolutionarily conserved GC-rich sequence block immediately downstream from the rep/ori promoter. These transactions are strictly dependent upon mitochondrial transcription.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
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Transcripción Genética
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ADN Mitocondrial
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ARN
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Proteínas de Saccharomyces cerevisiae
Idioma:
En
Revista:
Mol Cell Biol
Año:
1998
Tipo del documento:
Article
País de afiliación:
Estados Unidos