The male copulatory behavior of the nematode Caenorhabditis Elegans has been characterized as a series of stereotypic steps including response to contact with the hermaphrodite, vurval localization, spicule protrusion (male reproductive organ), and sperm transfer (Liu and Sternberg, Neuron, 1995). The differential functions of various cells have been investigated by characterizing defects resulting from targeted cell ablation. The purpose of my study is to investigate the molecular mechanics of such behavioral deficits by characterizing defects in the male copulatory sequence induced by inactivation of membrane receptors differentially expressed in male sensory neurons. Microinjection of double-stranded RNA has been shown to effect potent and specific interference with the function of endogenous genes (Fire et. al., Nature 1998). Accordingly, a mixture of dsRNA for the genes osm-6, sra-6, and srd-1 was injected into the gonads of adult plg-1; him-5 hermaphrodites. The male offspring born within thirty-two hours of injection were selected for scoring. At two days of age, each viable male was scored on a thin smear of bacteria with five to eight unc-31 hermaphrodites, a strain characterized by slow and uncoordinated movement which facilitates successful copulation. Each male was scored for ten minutes or until a successful sperm transfer had transpired. The male progeny of uninjected plg-1; him-5 hermaphrodites were scored as controls. The copulatory behavior of the injected hermaphrodites' progeny was defective in two respects. First, I characterize as failures to respond at least two consecutive contacts with hermaphrodite without pause or apparent attempt to search for the vulva. Six of twenty-one males (28.6%) failed to respond (wild-type = 10%). Secondly, I characterize as difficulty in turning (at either end of the hermaphrodite) either falling off, i.e. loss of contact, or a spiraling movement resulting in a double-coil around her head or tail. Three of six (50%) males exhibited difficulty in turning (wild-type = 10%). I infer that these behavioral deficits correspond to a loss of the function associated with one or more of the receptors encoded by osm-6, sra-6, and srd-1. Their role may be more precisely defined by assaying for defects associated with inactivation of single genes separately by the dsRNA injection method outlined here.
|Original language||English (US)|
|Journal||Journal of Investigative Medicine|
|State||Published - Feb 1999|
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)