Markers of ER stress are elevated in sec63st67 mutants. (A) RT-PCR showing expression of spliced and unspliced xbp-1 in individual larvae of the indicated genotypes and developmental stages. During the UPR, a 26-nucleotide fragment of xbp-1 mRNA is spliced. RT-PCR shows that the spliced form of xbp-1 (S) is enriched in sec63st67 mutants compared with wild-type (WT) and st67/+ larvae. Unspliced xbp-1 (US) is present in all samples. As a positive control for the assay, wild-type larvae treated with the ER stressor tunicamycin show upregulation of the spliced form of xbp-1. (B,C) qRT-PCR showing relative expression of UPR markers bip (B) and chop (C) in wild-type and heterozygous siblings (WT) vs sec63st67 mutant larvae (st67) at the indicated stages. Error bars indicate s.d.
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