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Abstract:
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Arabidopsis thaliana has four genes with close homology to human histone H3 lysine 4 demethylase
(HsLSD1), a component of various transcriptional corepressor complexes that often also contain
CoREST. All four A. thaliana proteins (AtLSD1-4) contain a flavin amine oxidase domain and a
SWIRM domain, the latter being present in proteins involved in chromatin regulation. Biochemical
characterization of recombinant AtLSD1 showed that it has demethylase activity toward mono- and
dimethylated Lys4 of histone 3. Modeling of AtLSD1 three-dimensional structure using the HsLSD1
crystal structure revealed some important differences, such as the lack of the HsLSD1 Tower domain,
which has been shown to interact with CoREST and to be indispensable for HsLSD1 demethylase
activity. This observation, together with AtLSD1 peculiar surface electrostatic potential distribution,
suggests that AtLSD1 molecular partners are different from those of HsLSD1. To get insight into the
AtLSD1 molecular partners, transgenic Arabidopsis plants over-expressing AtLSD1 are in preparation.
Characterization of Arabidopsis knock out mutants for all four AtLSDs is also in progress to study their
physiological role.
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