cDNA sequences encompassing the full coding region for the human muscle acetylcholine receptor (AChR) ɛ and γ subunits have been isolated. The deduced amino-acid sequences indicate that the mature ɛ subunit contains 473 amino acids and is preceded by a 20-amino-acid signal peptide. As predicted from genomic clones, the γ subunit contains 495 amino acids preceded by a 22-amino-acid signal peptide. In common with the human α, β, γ, and δ subunits the ɛ subunit is highly conserved between mammalian species. The ɛ subunit gene is not closely linked to the γ and δ subunits on chromosome 2 but rather is located with the β subunit on chromosome 17. Expression of the α-, β-, γ-, δ-, and ɛ-subunit cRNAs in rabbit-reticulocyte lysates followed by analysis on SDS/PAGE show glycosylated proteins with apparent molecular masses of 44–60 kDa.