In vivo construction of recombinant molecules within the Caenorhabditis elegans germ line using short regions of terminal homology

Homologous recombination provides a means for the in vivo construction of recombinant DNA molecules that may be problematic to assemble in vitro. We have investigated the efficiency of recombination within the Caenorhabditis elegans germ line as a function of the length of homology between recombining molecules. Our findings indicate that recombination can occur between molecules that share only 10 bp of terminal homology, and that 25 bp is sufficient to mediate relatively high levels of recombination. Recombination occurs with lower efficiency when the location of the homologous segment is subterminal or internal. As in yeast, recombination can also be mediated by either single- or double-stranded bridging oligonucleotides. We find that ligation between cohesive ends is highly efficient and does not require that the ends be phosphorylated; furthermore, precise intermolecular ligation between injected molecules that have blunt ends can also occur within the germ line

Magnesium Excretion in C. elegans Requires the Activity of the GTL-2 TRPM Channel

Systemic magnesium homeostasis in mammals is primarily governed by the activities of the TRPM6 and TRPM7 cation channels, which mediate both uptake by the intestinal epithelial cells and reabsorption by the distal convoluted tubule cells in the kidney. In the nematode, C. elegans, intestinal magnesium uptake is dependent on the activities of the TRPM channel proteins, GON-2 and GTL-1. In this paper we provide evidence that another member of the TRPM protein family, GTL-2, acts within the C. elegans excretory cell to mediate the excretion of excess magnesium. Thus, the activity of GTL-2 balances the activities of the paralogous TRPM channel proteins, GON-2 and GTL-1