Regulation of Gene Expression of Methionine Sulfoxide Reductases and Their New Putative Roles in Plants.

Ewa Kalemba,Ewelina Stolarska

doi:10.3390/ijms20061309

Abstract

Oxidation of methionine to methionine sulfoxide is a type of posttranslational modification reversed by methionine sulfoxide reductases (Msrs), which present an exceptionally high number of gene copies in plants. The side-form general antioxidant function-specific role of each Msr isoform has not been fully studied. Thirty homologous genes of Msr type A (MsrA) and type B (MsrB) that originate from the genomes of Arabidopsis thaliana, Populus trichocarpa, and Oryza sativa were analyzed in silico. From 109 to 201 transcription factors and responsive elements were predicted for each gene. Among the species, 220 and 190 common transcription factors and responsive elements were detected for the MsrA and MsrB isoforms, respectively. In a comparison of 14 MsrA and 16 MsrB genes, 424 transcription factors and responsive elements were reported in both types of genes, with almost ten times fewer unique elements. The transcription factors mainly comprised plant growth and development regulators, transcription factors important in stress responses with significant overrepresentation of the myeloblastosis viral oncogene homolog (MYB) and no apical meristem, Arabidopsis transcription activation factor and cup-shaped cotyledon (NAC) families and responsive elements sensitive to ethylene, jasmonate, sugar, and prolamine. Gene Ontology term-based functional classification revealed that cellular, metabolic, and developmental process terms and the response to stimulus term dominated in the biological process category. Available experimental transcriptomic and proteomic data, in combination with a set of predictions, gave coherent results validating this research. Thus, new manners Msr gene expression regulation, as well as new putative roles of Msrs, are proposed.

Highlights

The oxidation of methionine (Met) to methionine sulfoxide (MetSO) is inevitable for organisms living in an aerobic environment
The largest numbers of TF binding sites and responsive elements (REs) were predicted for MsrB9 originating from Arabidopsis, MsrB3.2 originating from poplar, and MsrA5 originating from rice
This hypothesis is supported by the fact that the biological process analysis that is based on GO terms confirmed that the predicted TFs are involved in developmental processes that include cell differentiation and the system development subcategory, which consists of plant organ development, root system development, and shoot system development child terms in the GO classification system; this hypothesis is supported by literature data that show that PMSR2 partially regulates Arabidopsis development [26]

Summary

Introduction

The oxidation of methionine (Met) to methionine sulfoxide (MetSO) is inevitable for organisms living in an aerobic environment. The enzyme that catalyzes the reduction of MetSO to Met is methionine sulfoxide reductase (Msr). More Msr studies are related to animals, an extremely high number of Msr gene copies has been found in plants. Arabidopsis and rice have fourteen and six Msr genes, respectively [5]. Most of the MsrA and MsrB genes encode proteins, with masses of approximately 25 kDa and 15 kDa, respectively. Within each MsrA and MsrB plant family, the sequence identity among isoforms ranges between 1% and 15% [7]. MetSO studies in Arabidopsis under oxidative stress led to the identification of approximately 400 proteins containing this reversible posttranslational modification that are potential targets of Msrs [10]. The multiplicity of plant Msr isoforms allowed for us to suppose that the Msr system might be involved in the regulation of many aspects of plant life

Methods

Results

Discussion

Conclusion