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Department of Biology, Faculty of Sciences, Kyushu University Graduate
School, Hakozaki, Fukuoka 812-8581, Japan * Present address: Research Institute of Microbial Diseases, Osaka University,
Yamadaoka, Suita 565-0871, Japan
Author for correspondence (e-mail:
Accepted for publication 6 December 2002.
We designed an automatic system to measure body length, diametersand
volume of a C. elegans worm. By using this system, mutantswith an
increased body volume exceeding 50% were isolated. Fourof them are grossly
normal in morphology and development, growlonger to be almost twice as big,
and have weak egg-laying defectsand extended lifespan. All the four mutants
have a mutationin the egl-4 gene. We show that the egl-4
gene encodes cGMP-dependentprotein kinases. egl-4 promoter::gfp
fusion genes are mainlyexpressed in head neurons, hypodermis, intestine and
body wallmuscles. Procedures to analyze morphology and volume of majororgans
were developed. The results indicate that volumes ofintestine, hypodermis and
muscle and cell volumes in intestineand muscle are increased in the
egl-4 mutants, whereas cellnumbers are not. Experiments on genetic
interaction suggestthat the cGMP-EGL-4 signaling pathway represses body size
andlifespan through DBL-1/TGF-ß and insulin pathways,respectively.
Key Words: cGMP-dependent protein kinase Body size Lifespan C. elegans EGL-4 Big mutant
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