Map of recombinant DNA constructs expressed in ScN2a cells using the pSPOX vector. Filled bars, GPI attachment sequences from wild-type MoPrP or Mo Qa(+). Hatched bars: Transmembrane and cytoplasmic sequences from either Mo CD4, rabbit LDLR, human PIGR, or Mo Qa(−). Dotted bar, FLAG sequence of Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys. Bold horizontal lines represent spacer sequence of Ser-Ala-Gly-Ser-Ala. CHO, N-glycosylation sites. M, Met at codon 109 and 112 of SHaPrP.