Supplemental Material

This article contains the following supporting material:

• Supplemental Figure 1 - WIF-B cells do not express endogenous MAL. Control (a) or myc-tagged MAL-infected cells (b and c) were stained for MAL directly (a and b) or for the myc epitope (c). MAL labeling was only detected in cells expressing myc-tagged MAL (compare b and c). Arrows are pointing to specific labelling of MAL in overexpressing cells. In some instances, despite the high background levels, low levels of MAL were detected. The asterisk is marking a BC whose side that faces a MAL overexpressing cell is brightly labelled with both MAL and myc antibodies. In contrast, the other half of the BC, separated by tight junctions and contributed from an uninfected cell, lacks staining for either marker.