We report a rapid method for the direct multicolor imaging of multiple subnuclear genetic sequences using novel quantum dot-based fluorescence in situ hybridization (FISH) probes (QD-FISH). Short DNA oligonucleotides were attached on QDs and used in a single hybridization/detection step of target sites in situ. QD-FISH probes penetrate both intact interphase nuclei and metaphase chromosomes and showed good targeting of dense chromatin domains with minimal steric hindrances. We further demonstrated that QD's broad absorption spectra allowed different colored probes specific for distinct subnuclear genetic sequences to be simultaneously excited with a single excitation wavelength and imaged free of chromatic aberrations in a single exposure. Thus, these results demonstrate that QD-FISH probes are very effective in multicolor FISH applications. This work also documents new possibilities of using QD-FISH probes detection down to the single molecule level.
Bibliographical noteFunding Information:
The authors would like to thank Dr. Xavier Michalet, for his critical reading of this manuscript as well as help with data analysis, and Tal Paley for editorial assistance. Fluorescent microscopy was performed at the CNSI Advanced Light Microscopy/Spectroscopy Shared Facility at UCLA. This work was funded by the National Institute of Health, grant no. R01 EB000312-04.
- Quantum dots