title: Identification of a truncated form of Methionine Sulfoxide Reductase A expressed in mouse embryonic stem cells.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
authors.forename: Pingping
authors.initials: P
authors.lastname: Jia
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Jia
authors.forename: Keith A
authors.initials: KA
authors.lastname: Webster
authors.forename: Xupei
authors.initials: X
authors.lastname: Huang
authors.forename: Andrei A
authors.initials: AA
authors.lastname: Kochegarov
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Lemanski
authors.forename: Larry F
authors.initials: LF
authors.lastname: Lemanski
mesh_terms: D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism*; D051150:Methionine Sulfoxide Reductases / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D016133:Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D008715:Methionine; D051150:Methionine Sulfoxide Reductases