The SH mRNA of the respiratory syncytial virus (RSV) contains two translation initiation codons. Initiation of translation from the AUG codon more distal from the 5' terminus of the mRNA produces the truncated alternative of the small hydrophobic protein (SHt). SHt is only produced in small amounts, appears to localize to the membrane of the rough endoplasmic reticulum, and is not detectable on the surface of infected cells (Olmstedt and Collins, 1989). SHt protein can likely oligomerize (Collins and Mottet 1993). The function of the SHt isoform is unknown.