Diagenode

Caenorhabditis elegans Heterochromatin Protein 1 (HPL-2) links developmental plasticity, longevity and lipid metabolism.


Meister P, Schott S, Bedet C, Xiao Y, Rohner S, Bodennec S, Hudry B, Molin L, Solari F, Gasser SM, Palladino F

ABSTRACT: BACKGROUND: Heterochromatin protein 1 (HP1) family proteins have a well-characterized role in heterochromatin packaging and gene regulation. Their function in organismal development, however, is less well understood. Here we used genome-wide expression profiling to assess novel functions of the Caenorhabditis elegans HP1 homolog HPL-2 at specific developmental stages. RESULTS: We show that HPL-2 regulates the expression of germline genes, extracellular matrix components and genes involved in lipid metabolism. Comparison of our expression data with HPL-2 ChIP-on-chip profiles reveals that a significant number of genes up- and down-regulated in the absence of HPL-2 are bound by HPL-2. Germline genes are specifically up-regulated in hpl-2 mutants, consistent with the function of HPL-2 as a repressor of ectopic germ cell fate. In addition, microarray results and phenotypic analysis suggest that HPL-2 regulates the dauer developmental decision, a striking example of phenotypic plasticity in which environmental conditions determine developmental fate. HPL-2 acts in dauer at least partly through modulation of daf-2/IIS and TGF-SZ signaling pathways, major determinants of the dauer program. hpl-2 mutants also show increased longevity and altered lipid metabolism, hallmarks of the long-lived, stress resistant dauers. CONCLUSIONS: Our results suggest that the worm HP1 homologue HPL-2 may coordinately regulate dauer diapause, longevity and lipid metabolism, three processes dependent on developmental input and environmental conditions. Our findings are of general interest as a paradigm of how chromatin factors can both stabilize development by buffering environmental variation, and guide the organism through remodeling events that require plasticity of cell fate regulation.

Tags
Bioruptor
Chromatin Shearing
ChIP-qPCR

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Published
December, 2011

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