Em. Thompson et al., REAL-TIME IMAGING OF TRANSCRIPTIONAL ACTIVITY IN LIVE MOUSE PREIMPLANTATION EMBRYOS USING A SECRETED LUCIFERASE, Proceedings of the National Academy of Sciences of the United Statesof America, 92(5), 1995, pp. 1317-1321
Study of gene expression kinetics during preimplantation mammalian dev
elopment is difficult because of the limited amount of material and th
e usually destructive, static nature of molecular analyses. We describ
e continuous, noninvasive monitoring of gene expression in preimplanta
tion embryos by using a secreted luminescent reporter, Vargula lucifer
ase. Transgene expression profiles were followed by assaying aliquots
of culture medium or by direct visualization of Vargula luciferase sec
retion from living embryos in real time through photon imaging, With t
his approach, it is possible to observe epigenetic modulations of gene
expression and to link this over time to the developmental capacity o
f individual embryos. In addition, by developing a strategy where expr
ession from integrated transgenes is enhanced relative to that from no
nintegrated DNA, we provide evidence that rapid detection of transgene
integration prior to the blastocyst stage should be possible. Thus, i
maging of Vargula luciferase secretion may also be useful in the early
screening of embryos, for example, in the production of transgenic li
vestock.