Introduction: The gene
unc-79 has a pharmaceutical profile which indicate it is important in determining volatile anesthetic sensitivity. Binding studies by Eckenhoff have shown a difference in the binding of halothane in the
unc-79 mutant compared with the wildtype. Here we report the cloning and further characterization of the
unc-79 gene. Methods: Mutant rescue was done by the technique of Mello. RT PCR, Northern blots, subcloning and DNA sequencing were done by standard protocols. Each mutation was confirmed by sequencing in two directions and in two independent PCR reactions. Blast algorithm was used to analyze homologies between sequences of
unc-79 and other known genes. Results: The smallest fragment of DNA which rescues the
unc-79 phenotype was predicted to encode a single protein E03A3.6. Northern blots have shown that the predominant message from this gene is about 10KB in size. Two transposon induced
unc-79 alleles show a shift in size of this message consistent with insertion of a transposon in the message. RT PCR reveals that at least two splice forms exist for E03A3.6 but that the majority of the message is in an unspliced form. Sequencing has identified mutations in E03A3.6 in 3/5 EMS induced
unc-79 alleles. The proteins encoded by the E03A3.6 gene are not homologous to any currently known gene. One allele of
unc-8,
n491n1193 has a phenotype identical to
unc-79. Other alleles of
unc-8 have diverse genetic interactions with
unc-79, acting either as a suppressor or to give anovel phenotype. Discussion:
unc-79 has a phenotype identical to an allele of the degenerin subunit,
unc-8. Its anesthetic sensitivity, and that of
unc-8, is suppressed by
unc-1, a gene highly homologous to stomatin.
unc-79 has no known homologies; however, the genetic data support the hypothesis that
unc-79 is involved with
unc-1 and
unc-8 in ion channel regulation. It is unclear why the majority of the
unc-79 message is unspliced but this raises the possibility that splicing may be important in determining the expression pattern of the protein. ACKNOWLEDGEMENTS: The authors are indebted to Monica Driscoll and Nektarios Tavernarakis for ongoing critical discussions and for sharing unpublished data. MMS and PGM were supported by NIH grant GM45402.