Fig. 6. stet encodes a predicted transmembrane protein homolog of rho. (A) Predicted structure of the stet transmembrane protein, showing seven transmembrane domains, placing the N terminus and the C terminus on opposite sites of the membrane (TMpred, ExPASy Molecular Biology Server). Amino acid substitutes in sequenced stet alleles (Table 1) are indicated. (B) Intron-exon structure based on the sequence of the testis cDNA, with predicted start codon in exon 2, stop codon in exon 4, and indicating the splice site mutation between exon 3 and 4 in stet ⁸⁷¹ leading to a premature stop codon.