2002 West Coast Worm Meeting abstract 97
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
| 1 | Lewis and Clark College, Portland, OR |
| 2 | HHMI and FHCRC, Seattle, WA |
Lysosome-related organelles represent a diverse group of specialized, cell type specific organelles that share a significant number of characteristics with conventional lysosomes. The C. elegans intestinal-specific gut granule is a member of this group of organelles. Gut granules are acidified, contain lysosomal proteins, and are the terminal endocytic compartment. However, unlike other lysosomes in C. elegans, gut granule contents are birefringent and autofluorescent, and they are likely to have a specialized role in the digestive physiology of the animal.
To identify the pathways involved in the biogenesis of lysosome-related organelles, we screened for mutants with defects in gut granule assembly. From our screens we identified three glo (for Gut granule LOss) genes that are necessary for gut granule biogenesis. Here we present our analysis of glo-1. glo-1 mutants mislocalize gut granule contents to the intestinal lumen during embryogenesis. In addition, glo-1 larvae and adults lack birefringent and autofluorescent gut granules and do not contain acidified and terminal endocytic compartments in the intestine. Surprisingly, despite the loss of functional lysosomes in the intestine, glo-1 animals are viable and fertile.
In order to understand how glo-1 functions in gut granule biogenesis we cloned the wild-type glo-1 gene. glo-1 is predicted to encode a GTPase with significant similarity to Rab GTPases. Rabs play important roles regulating targeting, trafficking, and transport in the secretory and endocytic pathways. The phenotype of glo-1 mutants supports a similar function for GLO-1 in the biogenesis of gut granules.