Induced mitotic death of HeLa cells by abnormal expression of c-H-ras.
When HeLa cells were selected for stable expression of a neo gene, linked either to mutated or wt c-H-ras genes, morphological examination of selected clones from several experiments revealed formation of giant multinucleated cells. These morphological alterations culminate in cell death, as a consequence of mitotic catastrophe (or mitotic death). Although clones expressing the mutated gene produced significantly larger numbers of these giant cells, those transfected with the normal allele were also found to produce significantly more giant multinucleated cells than non-transfected HeLa cells. Northern blot analysis of mRNA revealed overexpression of the normal H-ras gene in these clones. Chromatin structure analysis of these clones showed gross alterations, including the presence of micronuclei and heteroploid nuclei. Interestingly, odd numbers of nuclei were found in colonies of these giant cells. In addition, alterations in cell cycle parameters were observed, including the appearance of a subpopulation of cells with an abnormal content of DNA, probably representing dying cells. Our data support the notion that abnormal expression of H-ras contributes to mitotic catastrophe and death of a subpopulation of HeLa cells.
Miranda
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EI
Department of Molecular Biology, Instituto de Investigaciones Biomédicas-UNAM, Ciudad Universitaria, 04510 Mexico City, Mexico.
Santana
C
C
Rojas
E
E
Hernández
S
S
Ostrosky-Wegman
P
P
García-Carrancá
A
A
D015152:Blotting, Northern; D002453:Cell Cycle / Q000235:genetics; D016923:Cell Death; D002467:Cell Nucleus / Q000648:ultrastructure; D002869:Chromosome Aberrations; D025063:Chromosome Disorders; D015870:Gene Expression; D011905:Genes, ras; D006367:HeLa Cells; D006801:Humans; D019868:Kanamycin Kinase; D007700:Kinetics; D008938:Mitosis / Q000235:genetics*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000096:biosynthesis; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000096:biosynthesis; D013997:Time Factors; D014162:Transfection
D011994:Recombinant Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); D019868:Kanamycin Kinase; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)