FIGURE 3.

Expression of XPT1 from serotypes A and D similarly complements the serotype A xpt1Δ mutant. Total membranes prepared from serotype A wild-type (XPT1), serotype A xpt1Δ (xpt1Δ), serotype A xpt1Δ cells expressing XPT1 from the same serotype (xpt1Δ pXPT1), and serotype A xpt1Δ cells expressing XPT1 from serotype D (xpt1Δ pXPT1 (D)) were assayed with UDP-[¹⁴C]Xyl and α-1,3-Man₂ in the absence (−) or presence (+) of MnCl₂, as described under “Experimental Procedures.” An autoradiograph of the products resolved by TLC is shown; no signal was detected in other regions of the plate beyond minor amounts of free Xyl or in the absence of the α-1,3-Man₂ acceptor (not shown). The filled triangle indicates the product of the manganese-dependent xylosyltransferase activity, and the open triangle indicates the product of the unrelated xylosyltransferase Cxt1p (see “Results”).