Document Detail

Budded karyoplasts from multinucleated fibroblast cells contain centrosomes and change their morphology to mitotic cells.
MedLine Citation:
PMID:  16316754     Owner:  NLM     Status:  MEDLINE    
Cell changes to accelerated rates of growth are determined by random, new gene mutations that have their origin in vitro in a morphologically visible process of cell alterations. It is a continuous process that, step by step, transforms the normal cell into extended life (EL) cells. These latter cells with limited life spans can further transform to immortalized cells (i.e., cell lines) by the same sequence of morphological cell changes. In contrast to human epithelial cells, fibroblasts in culture have not given rise spontaneously to EL cells. Therefore, it was assumed that some of the cell changes (i.e., cell indicators of the process of transformation) might not be present in near senescent fibroblast cell cultures. As a positive control to normal fibroblast expansion to senescence, the same cells were stressed by inadequate nutrition and confluence. Another positive control was cell indicators induced by SV40 infections. The consecutive sequence of the cell indicators in the transformation process reported previously were: (1) large polyploid cells with nuclei that contained more than two genomes, (2) fragmentation/amitosis of the polyploid nuclei to bi- and multinucleated cells (MNCs), and (3) nuclear budding (i.e., karyoplasts) from MNCs that gave rise to EL cell colonies with various longevities beyond the senescent phase. The present study shows that MNCs and karyoplasts were present in the near-senescent fibroblast cell cultures. Furthermore, new data on the following aspect of the cell transformation process are presented: (1) association of the nuclear fragmentation process with death of cells, (2) cytological markers that distinguish between fragmentation-MNCs versus MNCs from cell fusion, (3) cytological changes of karyoplasts that go through mitotic division to produce daughter cells, and (4) presence of two centrosomes (spindle polar bodies) in the budded karyoplasts. These new findings are discussed in regard to the nuclear fragmentation process in polyploid cells which gives rise to smaller, viable nuclei in MNCs with reduced numbers of whole genomes.
Kirsten H Walen
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Publication Detail:
Type:  Journal Article     Date:  2005-11-28
Journal Detail:
Title:  Cell biology international     Volume:  29     ISSN:  1065-6995     ISO Abbreviation:  Cell Biol. Int.     Publication Date:  2005 Dec 
Date Detail:
Created Date:  2005-12-07     Completed Date:  2006-04-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9307129     Medline TA:  Cell Biol Int     Country:  England    
Other Details:
Languages:  eng     Pagination:  1057-65     Citation Subset:  IM    
Viral and Rickettsial Disease Laboratory, California Department of Health Services, 850 Marina Bay Parkway, Richmond, CA 94804, USA.
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MeSH Terms
Biological Markers
Cell Aging / genetics,  physiology*
Cell Culture Techniques / methods
Cell Line, Transformed
Cell Nucleus / ultrastructure
Cell Transformation, Viral
Centrioles / physiology
Centrosome / ultrastructure*
Fibroblasts / ultrastructure*
Giant Cells / cytology,  metabolism
Simian virus 40 / physiology
Reg. No./Substance:
0/Biological Markers

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