I happen to have a GFP fusion that seems to localize specifically in
nucleoli. Pictures of the live cells look beautiful, nucleoli-targeting
signal appears to be artificial, protein does not seem to be toxic, but
I lack time and resources to extend the study of this fusion much
further (it came up as a cloning artifact in an unrelated project). If
anyone is willing to collaborate on studying and developing applications
for this protein, please e-mail me at U09577 at uic.edu.I would welcome any
collaboration, but it has to be approved by my superior.