Iron and ROS control of the DownSTream mRNA decay pathway is essential for plant fitness

Abstract

A new regulatory pathway involved in plant response to oxidative stress was revealed using the iron-induced Arabidopsis ferritin AtFER1 as a model. Using pharmacological and genetic approaches, the DownSTream (DST) cis-acting element in the 3'-untranslated region of the AtFER1 mRNA was shown to be involved in the degradation of this transcript, and oxidative stress triggers this destabilization. In the two previously identified trans-acting mutants (dst1 and dst2), AtFER1 mRNA stability is indeed impaired. Other iron-regulated genes containing putative DST sequences also displayed altered expression. Further physiological characterization identified this oxidative stress-induced DST-dependent degradation pathway as an essential regulatory mechanism to modulate mRNA accumulation patterns. Alteration of this control dramatically impacts plant oxidative physiology and growth. In conclusion, the DST-dependent mRNA stability control appears to be an essential mechanism that allows plants to cope with adverse environmental conditions.

Arabidopsis Ferritin 1 (AtFer1) Gene Regulation by the Phosphate Starvation Response 1 (AtPHR1) Transcription Factor Reveals a Direct Molecular Link between Iron and Phosphate Homeostasis

“…Plants were grown for 19 days in a control medium and treated for 3 h with 500 M Fe-citrate. This treatment was previously shown to de-repress the expression of the AtFer1 gene and leads to a strong increase in abundance of its transcript (4,5,23). In phr1-3 mutant, AtFer1 mRNA transcript abundance was strongly increased, and the level reached was close to the one observed in wild type plants, indicating that the effect of PHR1 on AtFer1 gene expression is not linked to a defect of the gene response to iron overload under phosphate starvation.…”

The RNA-editing Enzyme APOBEC1 Requires Heterogeneous Nuclear Ribonucleoprotein Q Isoform 6 for Efficient Interaction with Interleukin-8 mRNA

“…Next, a reporter plasmid containing only a part of the IL8 3Ј-UTR (nucleotides 513-854) (del 1) was constructed. This region contains two types of ciselements, namely a cluster of AREs and a downstream (DST) element (20). To evaluate whether one or both of these cis- …”

Copper and Iron Homeostasis in Plants: The Challenges of Oxidative Stress

“…This apparent paradox was explained by kinetic studies: this additional level of regulation by mRNA turnover, together with the activation of transcription, allows some proteins to accumulate only transiently in response to Fe or H 2 O 2 . Both Fe and H 2 O 2 signaling involve an oxidative step, since treatments with antioxidants abolished both the Fe-and the H 2 O 2 -mediated ferritin mRNA destabilization (74). Thus, the existence of two independent pathways is not yet established.…”