Dual Functions of Yeast tRNA Ligase in the Unfolded Protein Response: Unconventional Cytoplasmic Splicing of HAC1 Pre-mRNA Is Not Sufficient to Release Translational Attenuation

Unconventional cytoplasmic splicing of HAC1 mRNA is essential for the yeast unfolded protein response (UPR). The UPR requires translational regulation of unspliced and spliced forms of HAC1 mRNAs. Here we report that tRNA ligase, Rlg1p, which ligates HAC1 exons in its splicing, has another face as a translational regulator of HAC1 mRNA