title: DNA damage response in CD133 + stem/progenitor cells from umbilical cord blood: low level of endogenous foci and high recruitment of 53BP1.
abstract: Abstract Purpose: Human hematopoietic stem cells (HSC) are thought to be a major target of radiation-induced leukemogenesis and also provide a relevant cellular model for assessing cancer risk. Cluster of designation 133+ (CD133+) is a marker found in human progenitor and hematopoietic stem cells. Our study examined the repair of radiation-induced DNA double-strand breaks (DSB) in CD133 + umbilical cord blood cells (UCBC).
  
  
  METHODS
  After γ-irradiation, endogenous and induced DSB were evaluated in CD133 + UCBC, CD133 - UCBC and peripheral blood lymphocytes (PBL) in terms of phosphorylated histone 2A family member X (γH2AX) and tumor suppressor p53 binding protein 1 (53BP1) foci.
  
  
  RESULTS
  We found that repair signaling in CD133 + UCBC is different from CD133 - UCBC and PBL. These differences include lower endogenous DSB levels and higher 53BP1 recruitment.
  
  
  CONCLUSIONS
  Our data, together with a recent report on radiation-induced γH2AX and 53BP1 foci in CD34 + cells, indicate enhanced DNA repair capacity in HSC as compared to mature lymphocytes.
authors.affiliation: Laboratory of Molecular Genetics, Cancer Research Institute, Bratislava, Slovak Republic.
authors.forename: Stanislav A
authors.initials: SA
authors.lastname: Vasilyev
authors.forename: Miroslav
authors.initials: M
authors.lastname: Kubes
authors.forename: Eva
authors.initials: E
authors.lastname: Markova
authors.forename: Igor
authors.initials: I
authors.lastname: Belyaev
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D006023:Glycoproteins / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects*; D006801:Humans; D007231:Infant, Newborn; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D010455:Peptides / Q000378:metabolism*; D011247:Pregnancy; D021381:Protein Transport / Q000528:radiation effects; D000071857:Tumor Suppressor p53-Binding Protein 1
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D015415:Biomarkers; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; C000606023:PROM1 protein, human; D010455:Peptides; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1