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Identification of a truncated form of methionine sulfoxide reductase a expressed in mouse embryonic stem cells

Pingping Jia1, Chi Zhang2, Yuanyuan Jia1, Keith A Webster2, Xupei Huang3, Andrei A Kochegarov5, Sharon L Lemanski4 and Larry F Lemanski45*

Author Affiliations

1 Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA

2 Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL 33431, USA

3 Department of Biomedical Science, Florida Atlantic University; Boca Raton, FL 33101, USA

4 Department of Anatomy and Cell Biology and The Cardiovascular Research Center, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA

5 Department of Biological and Environmental Sciences, Texas A&M University-Commerce, Commerce, TX 75429-3011, USA

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Journal of Biomedical Science 2011, 18:46  doi:10.1186/1423-0127-18-46

Published: 22 June 2011



Methionine Sulfoxide Reductase A (MsrA), an enzyme in the Msr gene family, is important in the cellular anti-oxidative stress defense mechanism. It acts by reducing the oxidized methionine sulfoxide in proteins back to sulfide and by reducing the cellular level of reactive oxygen species. MsrA, the only enzyme in the Msr gene family that can reduce the S-form epimers of methionine sulfoxide, has been located in different cellular compartments including mitochondria, cytosol and nuclei of various cell lines.


In the present study, we have isolated a truncated form of the MsrA transcript from cultured mouse embryonic stem cells and performed eGFP fusion protein expression, confocal microscopy and real time RT-PCR studies.


Results show a different expression response of this truncated transcript to oxygen deprivation and reoxygenation treatments in stem cells, compared to the longer full length form. In addition, a different subcellular localization pattern was noted with most of the eGFP fusion protein detected in the cytosol.


One possibility for the existence of a truncated form of the MsrA transcripts could be that with a smaller protein size, yet retaining a GCWFG action site, this protein might have easier access to oxidize methionine residues on proteins than the longer form of the MsrA protein, thus having an evolutionary selection advantage. This research opens the door for further study on the role and function of the truncated MsrA embryonic mouse stem cells.