| Abstract: |
Three human RecQ DNA helicases, WRN, BLM and RTS, are involved in the genetic disorders associated with genomic instability and a high incidence of cancer. RecQL1 and RecQL5 also belong to the human RecQ helicase family, but their correlation with genetic disorders, if any, is unknown. We report here that in human B cells transformed by Epstein-Barr virus (EBV), human fibroblasts and umbilical endothelial cells transformed by simian virus 40, the expression of WRN, BLM, RTS and RecQL1 was sharply up-regulated. In B cells this expression was stimulated within 5-40 h by the tumor promoting agent phorbol myristic acetate (PMA). Interestingly, RecQL5β, an alternative splicing product of RecQL5 with a nuclear localization signal, is expressed in resting B cells without significant modulation of its synthesis by EBV or PMA, suggesting it has a role in resting cells. We also roughly determined the number of copies per cell for the five RecQ helicase in B cells. In addition, levels of the different RecQ helicases are modulated in different ways during the cell cycle of actively proliferating fibroblasts and umbilical endothelial cells. Our results support the view that the levels of WRN, BLM, RTS and RecQL1 are differentially up-regulated to guarantee genomic stability in cells that are transformed or actively proliferating. |
| Keywords: |
protein expression; unclassified drug; human cell; cancer incidence; protein localization; cell cycle; cell division; gene product; b lymphocyte; b-lymphocytes; endothelium cell; gene expression regulation, neoplastic; genetic transfection; endothelium, vascular; umbilical veins; dna viruses; cell transformation; alternative splicing; alternative rna splicing; immunoblotting; fibroblast; simian virus 40; fibroblasts; cell line, transformed; helicase; recq helicases; adenosine triphosphatases; epstein barr virus; dna helicases; cell transformation, viral; herpesvirus 4, human; enzyme induction; phorbol 13 acetate 12 myristate; tetradecanoylphorbol acetate; gene expression regulation, enzymologic; genomic stability; human herpesvirus 4; recq helicase; rothmund thomson syndrome; werner syndrome; dna content; bloom syndrome; simiae; werner syndrome protein; protein blm; simian virus; humans; human; priority journal; article; protein recql1; protein recql5; protein rts
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