L. Armstrong et al., mTert expression correlates with telomerase activity during the differentiation of murine embryonic stem cells, MECH DEVEL, 97(1-2), 2000, pp. 109-116
Telomerase, the enzyme which maintains the ends of linear chromosomes in eu
karyotic cells, is found at low levels in somatic stem cells but while this
is incapable of preventing the progressive erosion of telomeres occurring
as a consequence of cell division, such cells show greater proliferative ca
pacity than normal somatic cells hence examination of telomerase activity i
n such stem cells is of interest. Our aim in this work was to examine the r
elationship between expression of the reverse transcriptase component (mTer
t) of murine telomerase. We report here the insertion of a reporter cassett
e comprising a segment of the promoter sequence of murine Tert gene coupled
to the coding sequence of green fluorescent protein (GFP) into murine embr
yonic stem (ES) cells and show that this is sufficient for mimicking the ex
pression of mTert. We show that the expression of mTert is very closely lin
ked to telomerase activity and that both are substantially reduced upon dif
ferentiation of ES cells into more committed lineages giving us a potential
reporter system for the selection and isolation of ES cells possessing dif
ferent levels of telomerase activity. (C) 2000 Elsevier Science Ireland Ltd
. All rights reserved.