Protein lipoilation in the nematode Caenorhabditis elegans

LAVATELLI, A; DE MENDOZA, D; MANSILLA, MC

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2014

SAIB

Lipoic acid (LA) is a sulfur-containing cofactor derived from octanoic acid required for the function of several multienzymes complexes involved in oxidative metabolism.  As lipoylation pathways remain unclear in eukaryotes, we propose the use of Caenorhabditis elegans as a model for studying them. The ability of synthesizing LA was confirmed by growing worms in minimal medium supplemented with acetate and succinate (M9sup) and feeding them with a bacterial strain auxotroph for LA. By in silico analyses of the C. elegans proteome we found several enzymes possibly involved in lipoylation. M01F1.3 appeared to have homology with bacterial and yeast lipoyl synthases. To analyze its importance in C. elegans, we performed RNA interference (RNAi) experiments. When grown at 15°C in M9sup and fed with the E. coli strains HT115 or AL100 (a HT115 derivative unable to synthetize LA), the worms arrested in the second generation as L4 larvae. The same phenotype was obtained when RNAi was done in NGM, a rich medium that has peptone, and hence, LA. It was not possible to rescue the arrested larvae by adding neither branched chain fatty acid precursors to M9sup, nor LA. Curiously, worms subjected to RNAi grown at 25°C in M9sup and fed with AL100, did become adults and were capable of laying eggs. It can be concluded that, at least at 15°C, M01F1.3 is essential for the normal development of worms.