Worm Breeder's Gazette 13(2): 73 (February 1, 1994)
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
mec-4 is a member of a multi-gene family in C. elegans that is required for the function of the six mechanosensory neurons. This family of genes has been named the degenerin family because two of the first identified members, deg-1 and mec-4 ,could mutate to induce neuronal degeneration. The C. elegans degenerins show sequence similarity to alpha-rENaC, which encodes the a subunit of the rat epithelial sodium channel. The rat channel has recently been shown to require two additional homologous subunits, alpha-rENaC and gamma-rENaC, for full channel activity in oocytes (Canessa et al., Nature, in press). Interestingly, M. Huang and M. Chalfie have reported that mec-10 encodes a second degenerin expressed in the touch receptors (Huang and Chalfie, Nature, in press). Moreover, genetic evidence suggests that MEC-4 and MEC-10 may interact. Thus, it is looking like at least two homologous subunits are part of the functional channel. It seems like a good bet that there is at least one more degenerin expressed in the touch receptor neurons.
We have been looking for additional members of the C. elegans degenerin family using an anchored PCR approach. Degenerate primers corresponding to conserved domains in front of the second membrane-spanning domain and a primer that matches the vector sequences of a given cDNA library are used to amplify sequences at the 3' ends of the genes. A conserved pattern of amino acids within the second membrane-spanning domain is included within amplified sequences and is used as one criterion for degenerin candidates. Thus far, we have identified three genes that exhibit a reasonable degree of similarity to reported degenerins but are clearly distinct from these genes. Additional sequence data is being generated and the map positions of these genes are being determined.