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Reduced mitotic activity at the periphery of human embryonic stem cell colonies cultured in vitro with mitotically‐inactivated murine embryonic fibroblast feeder cells
Author(s) -
Heng Boon Chin,
Cao Tong,
Liu Hua,
Rufaihah Abdul Jalil
Publication year - 2005
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1221
Subject(s) - mitosis , embryonic stem cell , biology , microbiology and biotechnology , cell division , stem cell , bromodeoxyuridine , mitotic index , in vitro , cell , cell culture , cell growth , genetics , gene
This study attempted to investigate whether different levels of mitotic activity exist within different physical regions of a human embryonic stem (hES) cell colony. Incorporation of 5‐bromo‐2‐deoxyuridine (BrdU) within newly‐synthesized DNA, followed by immunocytochemical staining was used as a means of detecting mitotically‐active cells within hES colonies. The results showed rather surprisingly that the highest levels of mitotic activity are primarily concentrated within the central regions of hES colonies, whereas the peripheral regions exhibited reduced levels of cellular proliferation. Two hypothetical mechanisms are therefore proposed for hES colony growth and expansion. Firstly, it is envisaged that the less mitotically‐active hES cells at the periphery of the colony are continually migrating outwards, thereby providing space for newly‐divided daughter cells within the more mitotically‐active central region of the hES colony. Secondly, it is proposed that the newly‐divided hES cells within the central region of the colony somehow migrate to the outer periphery. This could possibly explain why the periphery of hES colonies are less mitotically‐active, since there would obviously be an extended time‐lag before newly‐divided daughter cells are ready again for the next cell division. Further investigations need to be carried out to characterize the atypical mechanisms by which hES colonies grow and expand in size. Copyright © 2004 John Wiley & Sons, Ltd.