Collateral damage: spread of repeat-induced point mutation from a duplicated DNA sequence into an adjoining single-copy gene in Neurospora crassa.
J Biosci
; 30(1): 15-20, 2005 Feb.
Article
en En
| MEDLINE
| ID: mdl-15824437
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.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Recombinación Genética
/
ADN de Hongos
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Secuencias Repetitivas de Ácidos Nucleicos
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Mutación Puntual
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Neurospora crassa
Idioma:
En
Revista:
J Biosci
Año:
2005
Tipo del documento:
Article
País de afiliación:
India