In vivo levels of S-adenosylmethionine modulate C:G to T:A mutations associated with repeat-induced point mutation in Neurospora crassa.
Mutat Res
; 548(1-2): 85-95, 2004 Apr 14.
Article
in En
| MEDLINE
| ID: mdl-15063139
In Neurospora crassa, the mutagenic process termed repeat-induced point mutation (RIP) inactivates duplicated DNA sequences during the sexual cycle by the introduction of C:G to T:A transition mutations. In this work, we have used a collection of N. crassa strains exhibiting a wide range of cellular levels of S-adenosylmethionine (AdoMet), the universal donor of methyl groups, to explore whether frequencies of RIP are dependent on the cellular levels of this metabolite. Mutant strains met-7 and eth-1 carry mutations in genes of the AdoMet pathway and have low levels of AdoMet. Wild type strains with high levels of AdoMet were constructed by introducing a chimeric transgene of the AdoMet synthetase (AdoMet-S) gene fused to the constitutive promoter trpC from Aspergillus nidulans. Crosses of these strains against tester duplications of the pan-2 and am genes showed that frequencies of RIP, as well as the total number of C:G to T:A transition mutations found in randomly selected am(RIP) alleles, are inversely correlated to the cellular level of AdoMet. These results indicate that AdoMet modulates the biochemical pathway leading to RIP.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
S-Adenosylmethionine
/
DNA, Fungal
/
Repetitive Sequences, Nucleic Acid
/
Point Mutation
/
Methionine Adenosyltransferase
/
Neurospora crassa
Type of study:
Risk_factors_studies
Language:
En
Journal:
Mutat Res
Year:
2004
Document type:
Article
Affiliation country:
Argentina
Country of publication:
Netherlands