Dear David,

My 2 cents: Be aware that not only the GFP variant but also the method
by which the gfp is transferred into the cells, as well as expression
levels, may have a strong influence on the appearance of cellular
membranes and lipid metabolism. Adenovirus is nice because of its high
transfection efficiency but exactly that may be your problem at the same
time. It may be (it generally is) worthwhile to take the effort and
produce stable lines or at least try different methods to make the cells
express the FP.

Best, jens

-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]]
On Behalf Of David Burk
Sent: Thursday, November 20, 2008 8:31 PM
To: [log in to unmask]
Subject: GFP and lipid localization?

GFP Experts:

We have a group transfecting cells with adenovirus.  This virus contains
an EGFP sequence to let you know that, yes, the cell was transfected.
We have noticed in some of the transfected cells that the GFP signal
appears to be strongly associated with lipid droplets.  This is new to
me as I wouldn't expect WT-GFP to strongly associate with any particular
subcellular organelle and is confounding their work since they are
primarily interested in - of course - lipid droplets.

Do any of you know of a reason we would see wild-type GFP with no
targeting sequence or modifications labeling lipid droplets?  We are
beginning some additional control experiments with a large titration
range of virus to determine if the lipid labeling is related to vector
concentration (~GFP expression level).

Thanks for your help!

David H. Burk