Dear List,

I am about to prepare two DNA oligos internally labeled with four FITC-dT or TAMRA-dT per 55 nts long oligo.

Does anyone have any experience in double labeling FISH to detect two RNA species in a transfected cell? Does PMT is sensitive enough to detect an RNA molecule highlighted by 4 TAMRA molecules. 

What's about photo-stability and brightness of the dyes mentioned above. I am particularly worried about the TAMRA dye.

Would FITC and TAMRA quench each other when placed 10-12 nts apart?

Thanks a lot,

Vitaly

NCI-Frederick