Meeting Abstract

P3.69  Friday, Jan. 6  Disrupting gene function in tardigrades by RNA interference TENLEN, J.R.*; GOLDSTEIN, B.; Univ. of North Carolina, Chapel Hill; Univ. of North Carolina, Chapel Hill

How morphological diversity arises is a key question in evolutionary developmental biology. As a long-term approach to address this question, we are developing a close relative of both Drosophila (Phylum Arthropoda) and C. elegans (Phylum Nematoda), the water bear Hypsibius dujardini (Phylum Tardigrada), as a model system. We expect that using a close relative of two well-studied model systems will facilitate identifying genes relevant to understanding the evolution of development. Methods for disrupting gene activity are essential to this effort. No such method yet exists in Phylum Tardigrada. Here, we report that tardigrade gene function can be disrupted by RNA interference (RNAi). From H. dujardini ESTs present in GenBank, we identified and amplified putative homologs of several genes encoding proteins known to affect development in other organisms. We adapted protocols used in C. elegans for RNAi by microinjection of dsRNA, using a chamber we developed to hold anaesthetized animals during injection. Significant embryonic lethality was observed in progeny of H. dujardini adult females injected with dsRNA targeting genes encoding actin, Mago nashi, myosin or a 14-3-3 protein. Each experiment resulted in distinct terminal embryonic phenotypes that were consistent with predicted functions, suggesting that RNAi was gene-specific. Conversely, progeny of females injected with water or with dsRNA targeting green fluorescent protein developed normally. Experiments are in progress to determine the degree to which RNAi depletes target mRNAs. These studies present the first evidence that gene function can be disrupted by RNAi in Phylum Tardigrada, providing a method to dissect developmental gene functions in an organism that may sit at a key position in animal evolution for evo-devo studies.