Chromatin supraorganization, mitotic abnormalities and proliferation in cells with increased or down-regulated lox expression: Indirect evidence of a LOX-histone H1 interaction in vivo

Maria Luiza S Mello, Elenice M. Alvarenga, Benedicto de Campos Vidal, Armando Di Donato

Research output: Contribution to journalArticlepeer-review

Abstract

Lysyl oxidases (LOXs) are enzymes that permit the covalent crosslinking of the component chains of collagen and elastin. These enzymes are present inside the nuclei of certain mammalian cells. Previous studies have proposed LOX binding to histone H1 in vitro, and histone H1 is known to control global chromatin compaction and mitotic chromosome architecture. Therefore, in the present study, we analyzed chromatin supraorganizational changes, mitotic abnormalities, mitotic indices and cell death ratios in COS-7 and NRK-49F cells with high and low lox expression levels, respectively. The objective was to support biochemical data of LOX-H1 interaction, by providing evidence of chromatin remodeling in vivo, under different lox expressions. Chromatin decondensation assessed by image analysis was observed in COS-7 cells with increased lox expression. This decondensation is suggested to be promoted by LOX actions on histone H1, which loosens the DNA-H1 complex. In NRK-49F cells transfected with antisense lox or subjected to treatment with beta-aminopropionitrile (BAPN), chromatin condensation and nuclear phenotypic variability were found, which may be due to reduced LOX-H1 interaction. When lox expression was increased in COS-7 cells, the frequency of irregular chromosome plates was not affected, but cell proliferation decreased and " cell death preceded by multinucleation" increased. In NRK-49F cells there was accelerated proliferation induced by transfection with the antisense lox, and confirmed when cells were treated with BAPN. Apoptosis increased in NRK-49F cells only with BAPN treatment whereas cell death preceded by multinucleation increased only after antisense lox transfection. The data presented herein regarding chromatin remodeling indirectly support the hypothesis that LOX binds to histone H1 in vivo. Cell proliferation in COS-7 and NRK-49F cells and cell death at least in COS-7 cells agree with predicted effects of LOX interference in these processes.

Original languageEnglish
Pages (from-to)8-16
Number of pages9
JournalMicron
Volume42
Issue number1
DOIs
Publication statusPublished - Jan 2011

Keywords

  • Cell proliferation
  • Chromatin supraorganization
  • Chromosome abnormalities
  • Histone H1
  • Image analysis
  • Lox

ASJC Scopus subject areas

  • Cell Biology
  • Structural Biology

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