Action mechanism of upstream open reading frame from S-adenosylmethionine decarboxylase gene as a in vivo translational inhibitor

The eIF2 initiation complex is central to maintaining a functional translation machinery. Extreme stress such as life-threatening sepsis exposes vulnerabilities in this tightly regulated system, resulting in an imbalance between the opposing actions of kinases and phosphatases on the main regulatory subunit eIF2α. Here, we report that translation shutdown is a hallmark of established sepsis-induced kidney injury brought about by excessive eIF2α phosphorylation and sustained by blunted expression of the counterregulatory phosphatase subunit Ppp1r15a. We determined that the blunted Ppp1r15a expression persists because of the presence of an upstream open reading frame (uORF). Overcoming this barrier with genetic approaches enabled the derepression of Ppp1r15a, salvaged translation and improved kidney function in an endotoxemia model. We also found that the loss of this uORF has broad effects on the composition and phosphorylation status of the immunopeptidome that extended beyond the eIF2α axis. Collectively, our findings define the breath and potency of the highly conserved Ppp1r15a uORF and provide a paradigm for the design of uORF-based translation rheostat strategies. The ability to accurately control the dynamics of translation during sepsis will open new paths for the development of therapies at codon level precision.

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Cell-specific translational regulation of S-adenosylmethionine decarboxylase mRNA. Dependence on translation and coding capacity of the cis-acting upstream open reading frame.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)54212-5 ◽

1993 ◽

Vol 268 (1) ◽

pp. 726-731 ◽

Cited By ~ 1

Author(s):

J.R. Hill ◽

D.R. Morris

Keyword(s):

Translational Regulation ◽

Open Reading Frame ◽

Upstream Open Reading Frame ◽

Reading Frame ◽

Cis Acting ◽

Adenosylmethionine Decarboxylase ◽

Coding Capacity

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Polyamine Regulation of Ribosome Pausing at the Upstream Open Reading Frame of S-Adenosylmethionine Decarboxylase

Journal of Biological Chemistry ◽

10.1074/jbc.m105944200 ◽

2001 ◽

Vol 276 (41) ◽

pp. 38036-38043 ◽

Cited By ~ 2

Author(s):

G. Lynn Law ◽

Alexa Raney ◽

Carrie Heusner ◽

David R. Morris

Keyword(s):

Open Reading Frame ◽

Upstream Open Reading Frame ◽

Reading Frame ◽

Adenosylmethionine Decarboxylase ◽

Ribosome Pausing

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Termination and Peptide Release at the Upstream Open Reading Frame Are Required for Downstream Translation on Synthetic Shunt-Competent mRNA Leaders

Molecular and Cellular Biology ◽

10.1128/mcb.20.17.6212-6223.2000 ◽

2000 ◽

Vol 20 (17) ◽

pp. 6212-6223 ◽

Cited By ~ 18

Author(s):

Maja Hemmings-Mieszczak ◽

Thomas Hohn ◽

Thomas Preiss

Keyword(s):

Stop Codon ◽

Cauliflower Mosaic Virus ◽

Open Reading Frame ◽

Upstream Open Reading Frame ◽

Reading Frame ◽

Codon Context ◽

Necessary And Sufficient ◽

Synthetic Mrna

ABSTRACT We have shown recently that a stable hairpin preceded by a short upstream open reading frame (uORF) promotes nonlinear ribosome migration or ribosome shunt on a synthetic mRNA leader (M. Hemmings-Mieszczak and T. Hohn, RNA 5:1149–1157, 1999). We have now used the model mRNA leader to study further the mechanism of shunting in vivo and in vitro. We show that a full cycle of translation of the uORF, including initiation, elongation, and termination, is a precondition for the ribosome shunt across the stem structure to initiate translation downstream. Specifically, AUG recognition and the proper release of the nascent peptide are necessary and sufficient for shunting. Furthermore, the stop codon context must not impede downstream reinitiation. Translation of the main ORF was inhibited by replacement of the uORF by coding sequences repressing reinitiation but stimulated by the presence of the virus-specific translational transactivator of reinitiation (cauliflower mosaic virus pVI). Our results indicate reinitiation as the mechanism of translation initiation on the synthetic shunt-competent mRNA leader and suggest that uORF-dependent shunting is more prevalent than previously anticipated. Within the above constraints, uORF-dependent shunting is quite tolerant of uORF and stem sequences and operates in systems as diverse as plants and fungi.

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