"The authors show that phosphorylation of two different HAC1 splicing intermediates is required for their degradation by the 5'-->3' exonuclease Xrn1 to enact opposing effects on the UPR. We also found that ligated but 2'-phosphorylated HAC1 mRNA is cleaved yielding a decay intermediate with both 5'- and 2'-phosphates at its 5'-end that inhibit 5'-->3' decay and suggesting that Ire1 degrades incompletely processed HAC1."xsd:string