The NURD (Nucleosome Remodeling and Deacetylase) complex remodels and. chemically modifies chromatin and has also been shown to control gene. expression. The C. elegans genome encodes two Mi2 homologs of the mammalian. central component of the NURD complex, namely LET-418/Mi2 and CHD-3/Mi2.. While
chd-3 mutants show no phenotype,
let-418 mutants exhibit a. pleiotropic phenotype, including L1 larval arrest, presence of ectopic P-. granule in somatic cells (Unhavaithaya et al., 2002), hypersensitivity to. RNAi (Arianna Caesar, pers. com.) and an enhanced dauer formation. (Brunschwig et al., in prep.). In addition to that, we found that
let-418. mutants show a stress resistance phenotype either as a single mutation or. in combination with
daf-2 mutations. This suggests that
let-418 interferes. with the insulin pathway, which regulates stress resistance in C. elegans.. We also tested
chd-3 mutants for a similar phenotype and we observed an. enhanced stress resistance only in a
daf-2 mutant background.. In order to test whether
let-418 and
chd-3 regulate downstream targets of. the insulin pathway, we analysed the transcription level of the small heat-. schock protein gene,
hsp-16.2 and the superoxyde dismutase gene,
sod-3. We. found elevated mRNA level of both genes in
let-418 mutants compared to N2. wild type worms, while no change is observed in
chd-3 mutants. We are. currently performing microarray analysis to get a complete expression. profile of
let-418 and
chd-3 mutants.. Alltogether, these results begin to uncover a role for chromatin remodeling. in the stress response process and suggest that
let-418 and
chd-3 regulate. the process in a different way.. Do not add objects such as pictures, boxes, headers, footers, footnotes,. etc.