title: Recruitment of HP1β to UVA-induced DNA lesions is independent of radiation-induced changes in A-type lamins.
abstract: BACKGROUND
  The optimal repair of DNA lesions is fundamental for physiological processes. We asked whether the recruitment of HP1β, 53BP1 and BMI1 proteins to ultraviolet (UVA)-induced DNA lesions requires functional A-type lamins.
  
  
  RESULTS
  We found that UVA irradiation of nuclear lamina abolished the fluorescence of mCherry-tagged A-type lamins and destroyed the nuclear lamina as also observed by electron microscopy studies. Similarly, an absence of endogenous A- and B-type lamins was found in irradiated regions by UVA. However, irradiation did not affect the recruitment of HP1β, 53BP1 and BMI1 to DNA lesions. The UVA-induced shrinkage of the nuclear lamina, which anchors chromatin, explains why UVA-micro-irradiated chromatin is relaxed. Conversely, additional experiments with γ-irradiation showed that the nuclear lamina remained intact and the genome-wide level of HP1β was stable. Fluorescence intensity of HP1β and BMI1 in UVA-induced DNA lesions and level of HP1β after γ-irradiation were unaffected by deficiency in A-type lamins, whereas those parameters of 53BP1 were changed.
  
  
  CONCLUSIONS
  We conclude that only the 53BP1 status in DNA lesions, induced by UVA or γ-rays, is affected by A-type lamin deficiency, which was not observed for heterochromatin-related proteins HP1β and BMI1.
authors.affiliation: Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 612 65, Czech Republic.
authors.forename: Petra
authors.initials: P
authors.lastname: Sehnalová
authors.forename: Soňa
authors.initials: S
authors.lastname: Legartová
authors.forename: Dušan
authors.initials: D
authors.lastname: Cmarko
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kozubek
authors.forename: Eva
authors.initials: E
authors.lastname: Bártová
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis / Q000378:metabolism*; D004247:DNA / Q000235:genetics; D004249:DNA Damage / Q000528:radiation effects*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000378:metabolism; D034904:Lamin Type A / Q000032:analysis / Q000378:metabolism*; D051379:Mice; D063150:Polycomb Repressive Complex 1 / Q000032:analysis / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000378:metabolism; D000071857:Tumor Suppressor p53-Binding Protein 1; D014466:Ultraviolet Rays
chemical_list: C489421:Bmi1 protein, mouse; C096188:Cbx1 protein, mouse; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D034904:Lamin Type A; D011518:Proto-Oncogene Proteins; C498302:Trp53bp1 protein, mouse; D000071857:Tumor Suppressor p53-Binding Protein 1; D004247:DNA; D063150:Polycomb Repressive Complex 1
keywords: Chromatin; DNA damage; HP1; Lamins; Protein mobility