C. elegans strains were maintained at 20uC on NG plates using Escherichia coli strain OP50 as the food source [37] . Strains used in this study were wild-type Bristol strain N2 [37] , atf-6(ok551), glp-4(bn2), ire-1(v33), pek-1(ok275), pmk-1(km25), sek-1(km4), SJ4005 (zcIs4 [hsp-4::GFP]) and xbp-1(zc12). atf-6(ok551) and pek-1(ok275) were each outcrossed a total of 6 times. SJ4005 was outcrossed an additional 4 times as it had been outcrossed twice upon receipt from the Caenorhabditis Genetics Center. xbp-1(zc12) was created by outcrossing strain SJ17 (xbp-1(zc12); zcIs4 [hsp-4::GFP]) four times and removing the integrated hsp-4::GFP during the outcrosses. Images were acquired with an Olympus BX60 microscope with the 106 objective linked to a 0.56 camera mount and a DVC camera. Worms were placed on 2% agarose pads containing 0.1% sodium azide for photography.