Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Perhaps somebody can help me make sense of this.   We have a GFP tagged
protein expressed in C. elegans embryos.  Since the GFP signal is not very
strong, we use an anti-GFP antibody and a FITC tagged secondary to better
see this particular protein.  When we visualize the FITC stain, we see nice
membrane localized staining with very minimal background.  We then switch
over to DAPI to look at the nuclear staining.  When we switch back to FITC,
all of the nuclei can now be seen in the FITC channel.  We are visualizing
with an epifluorescence system prior to doing confocal.  Any ideas what
might be happening?

Suzana Glavas