John S Satterlee et al. (2005) International Worm Meeting ""My favorite gene has a C. elegans homolog, please help me!""

Bethan Peach, Anne C Hart, Adriana K Jones, John S Satterlee, Jessica Koranda

[International Worm Meeting, 2005]

Many of us have heard the above request from colleagues who hope to employ the C. elegans model system to answer biological questions. The C. elegans Core Facility at MGH Cancer Center helps non-nematode researchers utilize C. elegans to investigate many different genes and biological questions. Our experiences have taught us valuable lessons, and required us to develop strategies for dealing with common problems. For example, which gene is the authentic C. elegans ortholog? What useful reagents and strains are available and how can they best be utilized? What is the most efficient way to identify an RNAi phenotype? Can we identify a panel of GFP-expressing strains to facilitate identification of tissue/cell specific RNAi phenotypes? What is the best way to characterize a deletion mutant? We will describe some of our successes in answering these questions using examples from our work investigating synMuv genes and other cancer-related signaling pathways.

Khursheed A Wani et al. (2005) International Worm Meeting "C. elegans A, B and B3- type cyclins have both distinct and overlapping functions"

Khursheed A Wani, Sander Van Den Heuvel, Monique A Lorson, John S Satterlee, Jessica Koranda

[International Worm Meeting, 2005]

We are interested in understanding the roles of different Cyclin-dependent kinase (Cdk) complexes in the developmental regulation of cell-cycle progression. The C. elegans cell cycle uses multiple Cdks and various cyclins, possibly representing the entire range of Cyclin/Cdk complexes in mammals. C. elegans and other metazoans express distinct A- and B-type cyclins, as well as a cyclin B3 protein that shares specific motifs with both other mitotic cyclins. The evolutionary conservation of these distinct cyclin subfamilies may point to specificity in function. However, genetic studies in Drosophila have demonstrated that neither cyclin B nor cyclin B3 is essential for viability, and that cyclin A, B and B3 all cooperate during mitosis [Jacobs et al, Genes Dev. 12(23),1998].In previous unpublished studies, we observed that C. elegans B-type cyclins CYB-1 and CYB-3 show similar developmental expression patterns and largely overlapping subcellular localizations. However, inactivation of either gene by RNAi resulted in specific meiotic and mitotic defects. Inhibition of both cyclins simultaneously resulted in an earlier and more dramatic cell-cycle arrest and resembled cdk-1/ncc-1 RNAi. These results indicated that cyb-1 and cyb-3 have specific as well as overlapping M-phase functions. We wanted to expand these observations by including null mutations and characterization of cya-1 cyclin A. We generated a cya-1 deletion allele in a PCR-based approach. cya-1(he158) homozygous mutants and cya-1(RNAi) animals displayed a late larval arrest and protruding vulva phenotype. Stronger and more variable larval defects were seen in animals homozygous for either the cyb-1(gk35) or cyb-3(gk195) deletion allele (kindly provided by the C. elegans Knockout Consortium). Combination of cya-1 RNA and cyb-3(gk195) further increased the defects and resulted in a high percentage embryonic lethality. These results confirm and expand the RNAi-based observations, and indicate that cya-1, cyb-1 and cyb-3 each are individually required but also have overlapping functions.

Maaike C. W. van den Berg et al. (2006) European Worm Meeting "Sex-Dependent Resistance to the Fungal Pathogen Cryptococcus neoformans"

Maaike C. W. van den Berg, Jessica Z. Woerlee, Robin C. May, Hansong Ma

[European Worm Meeting, 2006]

Maaike C. W. van den Berg1,2, Jessica Z. Woerlee2, Hansong Ma1,2 & Robin C. May1. Cryptococcus neoformans is the causative agent of cryptococcosis, a fatal fungal disease of immunocompromised patients. Our group and others have made use of C. elegans as an alternative host for Cryptococcus, in order to investigate the molecular basis of host-pathogen interactions. Using this system, we now report that male C. elegans show greater resistance to killing by Cryptococcus than hermaphrodite animals and that this resistance can be induced in hermaphrodite animals by inappropriate activation of the male sex-determination pathway. Resistance is molecularly determined, rather than resulting from behavioural changes or reproductive differences, and requires the activity of the stress-response transcription factor DAF-16. Finally, we demonstrate that resistance to Cryptococcus neoformans correlates broadly with longevity within the Caenorhabditis genus. Our results suggest that many of the molecular determinants of longevity and immunity are the same and that differential regulation of these determinants may underlie much sex-dependent and species-dependent variation.