Yes, of course !
We also have such experience with ES clones transfected with EGFP-1
Don´t wonder.
It´s natural and well known "positional effect" due to
random insertion of EGFP under some active cells promoters.
Moreover, it´s a basis of known "genes trap"method to reveal
some actually active genes (up to now, though, applied mainly with LacZ
reporter gene).
Best regards,
Eugene Kolossov
Institute for Neurophysiology
University of Cologne
Robert-Koch-Str.39
50931 Cologne, Germany
tel: 49-221/478-3415
fax: 49-221/478-6965
e-mail:ek at physiologie.uni-koeln.de