Functional Assay of a Putative Drosophila Sodium Channel Gene in Homozygous Deficiency Neurons

Abstract

Using voltage-clamp techniques, we have examined embryonic sodium currents in neurons deficient for a gene located at 60E5/6 that shares extensive amino acid similarity with vertebrate sodium channel genes. These neurons expressed sodium currents similar to wildtype, supporting the hypothesis that para, and not the gene at 60E5/6, is the primary sodium channel gene expressed in embryonic neurons. A simple marking procedure allowing positive identification of the genotypes of cultured Drosophila embryos obtained from heterozygous parents was used to recognize cultures homozygous for deficiencies. The morphological development of both neurons and myotubes in these cultures was similar to wildtype, making it feasible to compare the properties of normal diploid cells and cells completely lacking a putative sodium channel gene.

Key Words:

• voltage-clamp
• β-galactosidase
• heat shock promoter