Phylogeny-linked occurrence of ribosome stalling on the mRNAs of Arabidopsis unfolded protein response factor bZIP60 orthologs in divergent plant species.

The bZIP60, XBP1 and HAC1 mRNAs encode transcription factors that mediate the unfolded protein response (UPR) in plants, animals and yeasts, respectively. Upon UPR, these mRNAs undergo unconventional cytoplasmic splicing on the endoplasmic reticulum (ER) to produce active transcription factors. Although cytoplasmic splicing is conserved, the ER targeting mechanism differs between XBP1 and HAC1.

Reverse genetics-based biochemical studies of the ribosomal exit tunnel constriction region in eukaryotic ribosome stalling: spatial allocation of the regulatory nascent peptide at the constriction.

A number of regulatory nascent peptides have been shown to regulate gene expression by causing programmed ribosome stalling during translation. Nascent peptide emerges from the ribosome through the exit tunnel, and one-third of the way along which β-loop structures of ribosomal proteins uL4 and uL22 protrude into the tunnel to form the constriction region. Structural studies have shown interactions between nascent peptides and the exit tunnel components including the constriction region.