Dietary regulation of hypodermal polyploidization in C. elegans.
BACKGROUND
Dietary restriction (DR) results in increased longevity, reduced fecundity and reduced growth in many organisms. Though many studies have examined the effects of DR on longevity and fecundity, few have investigated the effects on growth.


RESULTS
Here we use Caenorhabditis elegans to determine the mechanisms that regulate growth under DR. We show that rather than a reduction in cell number, decreased growth in wild type C. elegans under DR is correlated with lower levels of hypodermal polyploidization. We also show that mutants lacking wild type sensory ciliated neurons are small, exhibit hypo-polyploidization and more importantly, when grown under DR, reduce their levels of endoreduplication to a lesser extent than wild type, suggesting that these neurons are required for the regulation of hypodermal polyploidization in response to DR. Similarly, we also show that the cGMP-dependent protein kinase EGL-4 and the SMA/MAB signalling pathway regulate polyploidization under DR.


CONCLUSIONS
We show C. elegans is capable of actively responding to food levels to regulate adult ploidy. We suggest this response is dependent on the SMA/MAB signalling pathway.
Tain
Luke S
LS
Department of Biomedical Sciences, University of Sheffield, Sheffield, S10 2TN, UK. luke.tain@sheffield.ac.uk
Lozano
Encarnación
E
Sáez
Alberto G
AG
Leroi
Armand M
AM
D000818:Animals; D049628:Body Size; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D031204:Caloric Restriction; D002923:Cilia / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism; D020405:Dermis / Q000254:growth & development*; D004032:Diet; D005247:Feeding Behavior; D005298:Fertility; D005502:Food; D015801:Helminth Proteins / Q000378:metabolism; D008018:Life Cycle Stages; D008136:Longevity; D008954:Models, Biological; D009474:Neurons / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism; D011123:Polyploidy; D016212:Transforming Growth Factor beta / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; C117509:Dbl-1 protein, C elegans; D015801:Helminth Proteins; D009479:Neuropeptides; D016212:Transforming Growth Factor beta; C400683:che-2 protein, C elegans; D017869:Cyclic GMP-Dependent Protein Kinases; C470349:EGL-4 protein, C elegans