Regulation of growth by ploidy in Caenorhabditis elegans.
Some animals, such as the larvae of Drosophila melanogaster, the larvae of the Appendicularian chordate Oikopleura, and the adults of the nematode Caenorhabditis elegans, are unusual in that they grow largely by increases in cell size. The giant cells of such species are highly polyploid, having undergone repeated rounds of endoreduplication. Since germline polyploid strains tend to have large cells, it is often assumed that endoreduplication drives cell growth, but this remains controversial. We have previously shown that adult growth in C. elegans is associated with the endoreduplication of nuclei in the epidermal syncitium, hyp 7. We show here that this relationship is causal. Manipulation of somatic ploidy both upwards and downwards increases and decreases, respectively, adult body size. We also establish a quantitative relationship between ploidy and body size. Finally, we find that TGF-beta (DBL-1) and cyclin E (CYE-1) regulate body size via endoreduplication. To our knowledge, this is the first experimental evidence establishing a cause-and-effect relationship between somatic polyploidization and body size in a metazoan.
Lozano
Encarnación
E
Division of Biology, Silwood Park Campus, Imperial College London, Ascot, Berks SL5-7PY, United Kingdom.
Sáez
Alberto G
AG
Flemming
Anthony J
AJ
Cunha
Ana
A
Leroi
Armand M
AM
D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000502:physiology; D049108:Cell Enlargement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D019927:Cyclin E / Q000502:physiology; D004247:DNA / Q000096:biosynthesis; D005247:Feeding Behavior; D006918:Hydroxyurea / Q000494:pharmacology; D009479:Neuropeptides / Q000502:physiology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011003:Ploidies; D016212:Transforming Growth Factor beta / Q000502:physiology
D029742:Caenorhabditis elegans Proteins; D019927:Cyclin E; C117509:Dbl-1 protein, C elegans; D009479:Neuropeptides; D019384:Nucleic Acid Synthesis Inhibitors; D016212:Transforming Growth Factor beta; D004247:DNA; D006918:Hydroxyurea