High Resolution Fluorescence Imaging Of Cellular Dna And Rna Enabled By The Synthesis Of Complex Oligonucleotide Libraries

Fluorescence in situ Hybridization (FISH) is a powerful technique for studying the structure, organization, and localization of nucleic acids within individual cells. However, the use of FISH has often been dependent upon access to cloned template DNA for the generation of probes. Clones for specific regions may be unavailable, or the genomic region of interest may contain repetitive and other non-informative sequences which can be problematic for FISH analysis. We have leveraged our ability to chemically synthesize DNA in massively parallel reactions to produce libraries of oligonucleotides up to 200 bases in length that can be used to generate FISH probes. The sequences of the oligonucleotides in these libraries are selected in silico using empirically determined criteria so as to avoid repetitive elements or regions homologous to other non-targeted loci. Using oligonucleotide library-derived FISH probes on DNA, human genomic regions as small as 1.8 kb and as large as whole chromosomes can be visualized in both metaphase and interphase cells using the same simple assay protocol. Because of the inherent flexibility in our probe design methods, we readily visualized regions rich in repeats and/or GC content. Using oligonucleotide library-derived FISH probes on RNA, we have been able to detect the localization of a variety of both coding and non-coding RNAs in fixed cells, using both conventional fluorescence and structured illumination microscopy. Simultaneous hybridization of FISH probes labeled with different fluorophores enables visualization of multiple sequences at once. Using probes designed specifically to transcribed vs. non-transcribed regions, we have been able to simultaneously detect DNA and RNA from the same locus in the same FISH assay. Our oligo FISH methods are readily compatible with the co-detection of cellular proteins by immunocytochemistry. The ability to generate high performance FISH probes using chemically synthesized oligo libraries that can work flexibly with co-detection of other molecules yields a valuable tool for studies of how localization of specific nucleic acids impacts biological function. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2102. doi:1538-7445.AM2012-2102