A hypothesis for the tissue specificity of nematode parasites.
Recent work from Riddle and coworkers has shown that in the free-living soil nematode, Caenorhabditis elegans, the decision to become a developmentally arrested, dispersal form known as the dauer ("enduring") larva is controlled, at least in part, by transcription of a wild-type allele at the daf-7 locus. daf-7 mutants are "constitutive dauers." Using this model as a general paradigm for nematode development, I propose that many nematode parasites behave as though they were daf-7 mutants. This will ensure developmental arrest at the L3 stage. I further propose that these organisms obtain the daf-7 gene product required for reentry into the developmental pathway from the mammalian host and that their tissue localization is dictated by the daf-7 homologue that is uniquely recognized by the cognate receptor.
Rajan
T V
TV
Department of Pathology, University of Connecticut Health Center, Farmington 06030-3105, USA. rajan@cortex.uchc.edu
D000818:Animals; D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins / Q000235:genetics*; D007814:Larva / Q000502:physiology; D009154:Mutation; D009348:Nematoda / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000235:genetics*
D029742:Caenorhabditis elegans Proteins; C102095:DAF-7 protein, C elegans; D015801:Helminth Proteins; D016212:Transforming Growth Factor beta