PgmNr W4139: Genetic and molecular tools for Caenorhabditis sp. 34, a sister species of C. elegans with a larger body size.

Authors:
K. Tsuyama 1 ; S. Namai 1 ; R. Kumagai 1 ; T. Shimura 1 ; N. Kanzaki 2 ; T. Kikuchi 3 ; A. Sugimoto 1


Institutes
1) Tohoku University, Sendai, Miyagi, JP; 2) Forestry and Forest Products Research Institute, Tsukuba, Japan; 3) University of Miyazaki, Miyazaki, Japan.


Keyword: Other ( sister species )

Abstract:

Caenorhabditis sp. 34 is a sister species of C. elegans recently isolated from syconia of the fig Ficus septica on Ishigaki Island, Japan. Although their genome sequences are the closest each other, there are striking developmental and morphological differences between C. sp. 34 and C. elegans. For example, C. sp. 34 adults are two times longer than C. elegans; C. sp. 34 has female and male, unlike C. elegans that has hermaphrodite and male. The genome similarity and phenotype differences make this organism highly attractive as a satellite model for C. elegans in comparative and evolutionary biological studies.

To make C. sp. 34 more tractable, we are developing genetic and molecular tools for C. sp. 34, by emulating the rich experimental techniques established in C. elegans. 1) Immunofluorescence. A panel of antibodies against C. elegans proteins was used for immunofluorescence of C. sp. 34 embryos, many of which successfully recognized expected structures in C. sp. 34. Notably, polyclonal antibodies against C. elegans PGL-1/3 recognized P granule-like granules in C. sp. 34 embryos, but their size was smaller and more dispersed than their C. elegans counterparts, implying the distinct dynamics of germ granules between these two species. 2) Transgenesis. We examined transgenesis in C. sp. 34 by microinjecting transgenic marker plasmids commonly used in C. elegans. Although the frequency was lower than that in C. elegans, stable transgenic lines were obtained for all transgenes tested, and their expected phenotypes (Rol for rol-6(su1006)) or expression patterns (Psur-5::GFP (universal), Punc-122::GFP/RFP (coelomocytes), Pmyo-3::mCherry (body wall muscle), Podr-1::GFP (AWC neuron)) were detected. Thus, promoters and 3’-UTR sequences of C. elegans appear generally functional in C. sp. 34. 3) RNAi. We tested RNAi in C. sp. 34 using the soaking and feeding methods. The soaking RNAi of the tbg-1 (g-tubulin) ortholog of C. sp. 34 resulted in early embryonic lethality at a high penetrance, with phenotypes similar to those of tbg-1(RNAi) in C. elegans. Feeding RNAi for the GFP coding sequence in the GFP-transgenic C. sp. 34 animals efficiently reduced the GFP signal. Thus, C. sp. 34 is highly sensitive to RNAi via ingested dsRNAs.

Taken together, many of the genetic techniques, molecular tools and resources of C. elegans can be directly transferred to C. sp. 34. The relative feasibility of importing C. elegans techniques and resources will allow rapid establishment of C. sp. 34 as a satellite model species for evolutionary studies. Now we plan to use these techniques and tools for dissecting the genetic bases for morphological and developmental differences between C. sp. 34 and C. elegans.



Wormbase Genetic Index
1. pgl-1
2. pgl-3
3. rol-6
4. sur-5
5. unc-122
6. odr-1
7. tbg-1