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LESCANO, Ignacio

postdoctoral fellow FONCyT
Director: Maria Elena Alvarez

PhD Thesis Topic

Functional study of the DNA glycosylase MBD4 of Arabidopsis under abiotic stress
Epigenetic changes affect chromatin compaction, as well as the stability and expression of the genomes, without fixing mutations. Since epigenetic changes are rapid and reversible, and can be inherited, there is great interest in knowing their contribution to stress responses. 5-methylcytosine (5-mC) is one of the most studied epigenetic marks in eukaryotic genomes and generally inhibits gene expression and recombination. 5-mC is deposited by the DNA methyltransferases after DNA replication. Under some particular conditions that do not occur with replication, DNA glycosylases remove 5-mC of certain sites of the genome. MBD4 (Methyl-binding domain protein 4), a DNA glycosylase that has been studied intensively in mammals, binds to hypermethylated sites and affects gene expression. We have characterized a homologous nuclear protein in the model plant Arabidopsis thaliana (Atnbd4) that contributes to oxidative stress resistance, suggesting its participation in physiological and defense processes that have not yet been characterized. To study the in vivo function of AtMBD4 we are carrying out the following studies:
-Characterization of Arabidopsis phenotypes associated with the deficiency/overexpression of MBD4 under control and stress conditions
-Identification of MBD4 target genes presumably responsible for these phenotypes
-Contribution of MBD4 to the removal of repressive epigenetic marks of selected target genes
-Identification of proteins of interest associated with MBD4.