Collateral damage: spread of repeat-induced point mutation from a duplicated DNA sequence into an adjoining single-copy gene in Neurospora crassa.
J Biosci
;
2005 Feb; 30(1): 15-20
Article
Dans Anglais
| IMSEAR
| ID: sea-110672
ABSTRACT
Repeat-induced point mutation (RIP) is an unusual genome defense mechanism that was discovered in Neurospora crassa. RIP occurs during a sexual cross and induces numerous G C to A T mutations in duplicated DNA sequences and also methylates many of the remaining cytosine residues. We measured the susceptibility of the erg-3 gene, present in single copy, to the spread of RIP from duplications of adjoining sequences. Genomic segments of defined length (1, 1.5 or 2 kb) and located at defined distances (0, 0.5, 1 or 2 kb) upstream or downstream of the erg-3 open reading frame (ORF) were amplified by polymerase chain reaction (PCR), and the duplications were created by transformation of the amplified DNA. Crosses were made with the duplication strains and the frequency of erg-3 mutant progeny provided a measure of the spread of RIP from the duplicated segments into the erg-3 gene. Our results suggest that ordinarily RIP-spread does not occur. However, occasionally the mechanism that confines RIP to the duplicated segment seems to fail (frequency 0.1-0.8%) and then RIP can spread across as much as 1 kb of unduplicated DNA. Additionally, the bacterial hph gene appeared to be very susceptible to the spread of RIP-associated cytosine methylation.
Texte intégral:
Disponible
Indice:
IMSEAR (Asie du Sud-Est)
Sujet Principal:
Recombinaison génétique
/
ADN fongique
/
Séquence nucléotidique
/
Séquences répétées d'acides nucléiques
/
Mutation ponctuelle
/
Cytosine
/
Méthylation
/
Neurospora crassa
langue:
Anglais
Texte intégral:
J Biosci
Année:
2005
Type:
Article
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