Abstract
The migration of gonadal distal tip cells (DTCs) in Caenorhabditis elegans serves as an excellent model for studying the migration of epithelial tubes during organogenesis. Mutations in the mig-17/ADAMTS gene cause misdirected DTC migration during gonad formation, resulting in deformed gonad arms. An amino acid substitution in RPL-20, the ortholog of mammalian RPL18a/eL20, a component of the 60 S ribosomal large subunit, exhibited a slow-growth phenotype and strongly suppressed the mig-17 gonadal defects. Slow-growing mutations clk-1 and clk-2 also suppressed mig-17. Intestine-specific overexpression of mutant RPL-20 protein resulted in a slow-growth phenotype and suppressed the mig-17 gonadal defects, but these effects were much weaker when wild-type RPL-20 was overexpressed, suggesting that the mutant RPL-20 protein acquired a novel function. Analysis of ribosome profiles revealed reduced biogenesis of the 60 S subunit, leading to a reduction of 80 S ribosomes in the rpl-20 mutant. These results suggest that DTC migration defects in mig-17/ADAMTS mutants can be partly suppressed by growth retardation caused by the rpl-20 mutation. While defective ribosome biogenesis may contribute to the observed growth retardation, further investigation is needed to clarify the molecular basis of this phenomenon.