Plant-pathogen interaction leads to activation of specific genes followed by synthesis of proteins or enzymes engaged in host defense reactions. An important process of gene expression regulation involves chemical modifications of specific residues on histones that remodel chromatin from a tightly coiled, functionally repressive conformation (heterochromatin) to a relatively relaxed structure (euchromatin) that is readily accessible to transcription factors and hence biologically active. A vital step in understanding how genes are expressed or are not expressed (silent) was discovery of histone methylation, an initiating event in silencing of genes, and histone methyl transferase (HMT), the enzyme that drives methylation, is therefore of great topical interest. A conserved region of some 130 amino acid residues, termed the SET domain, is the core element of HMT.
The basic research of the laboratory is concerned with functional characterization of SET domain in Arabidopsis thaliana and is mainly focused on two recently discovered HMT isoforms in K23 mutant. These two isoforms, termed α and β, are apparently created by alternative RNA splicing.
The current work is concentrated on characterization of the functions of HMT K23 and of two additional Arabidopsis SuvR SET domain subfamily members and on determination if there is any interaction between the two isoforms, α and β. Since the domain architecture of HMT K23 closely parallels that of DIM-5 of Neurospora, the only HMT in this organism, the possible complementation with Neurospora mutants DIM-5 is also studied. If these experiments are successful, this approach can be used as a rapid screen for HMT activity of other plant (or animal) SET proteins.
In the field of applied research, the laboratory is involved in molecular biology of resistance against apple scab caused by the fungus Venturia inaequalis
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