Ypt1 associates in vivowith unspliced HAC1in a UPR–dependent manner.

GST-tagged Ypt1 was purified from yeast cells grown under normal (A) or UPR-induced conditions (B) using anti-GST conjugated beads. UPR was induced by addition of 10 mM DTT for 50 min. Co-purifying RNAs were labeled and bound to a DNA microarray. “Mock-corrected IP enrichment” values were calculated by subtracting Mock IP signal from Ypt1 IP signal on a gene-by-gene basis (see “Materials and Methods”). Arrows indicate enrichment values for HAC1 probes (“JXNs” = junctions, 5 probes total present on the arrays- 2 unspliced junctions, intron, ORF, and spliced junction).