Evidence for ovarian granulosa stem cells: telomerase activity and localization of the telomerase ribonucleic acid component in bovine ovarian follicles
We have previously postulated that granulosa cells of developing follicles arise from a population of stem cells. Stem cells and cancer cells can divide indefinitely partly because they express telomerase. Telomerase is a ribonucleoprotein enzyme that repairs the ends of telomeres that otherwise sho...
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Published in | Biology of reproduction Vol. 61; no. 2; pp. 358 - 366 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Madison, WI
Society for the Study of Reproduction
01.08.1999
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Subjects | |
Online Access | Get full text |
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Summary: | We have previously postulated that granulosa cells of developing follicles arise from a population of stem cells. Stem cells
and cancer cells can divide indefinitely partly because they express telomerase. Telomerase is a ribonucleoprotein enzyme
that repairs the ends of telomeres that otherwise shorten progressively upon each successive cell division. In this study
we carried out cell cycle analyses and examined telomerase expression to examine our hypothesis. Preantral (60â100 μm) and
small (1 mm) follicles, as well as granulosa cells from medium-sized (3 mm) and large (6â8 mm) follicles, were isolated. Cell
cycle analyses and expression of Ki-67, a cell cycle-related protein, were undertaken on follicles of each size (n = 3) by
flow cytometry; 12% to 16% of granulosa cells in all follicles were in the S phase, and less than 2% were in the G 2 /M phase. Telomerase activity (n = 3) was highest in the small preantral follicles, declining at the 1-mm stage and even further
at the 3-mm stage. In situ hybridization histochemistry was carried out on bovine ovaries, and telomerase RNA was detected
in the granulosa cells of growing follicles but not primordial follicles. Two major patterns of staining were observed in
the membrana granulosa of antral follicles: staining in the middle and antral layers, and staining in the middle and basal
layers. No staining was detected in oocytes. Our results strongly support our hypothesis that granulosa cells arise from a
population of stem cells. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0006-3363 1529-7268 |
DOI: | 10.1095/biolreprod61.2.358 |