Instrumentation and metrology for single RNA counting in biological complexes or nanoparticles by a single-molecule dual-view system
- 1Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana 47907, USA
- 2Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
- 3Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406, USA
Abstract
Limited by the spatial resolution of optical microscopy, direct detection or counting of single components in biological complexes or nanoparticles is challenging, especially for RNA, which is conformationally versatile and structurally flexible. We report here the assembly of a customized single-molecule dual-viewing total internal reflection fluorescence imaging system for direct counting of RNA building blocks. The RNA molecules were labeled with a single fluorophore by in vitro transcription in the presence of a fluorescent AMP. Precise calculation of identical or mixed pRNA building blocks of one, two, three, or six copies within the bacteriophage phi29 DNA packaging motor or other complexes was demonstrated by applying a photobleaching assay and evaluated by binomial distribution. The dual-viewing system for excitation and recording at different wavelengths simultaneously will enable the differentiation of different complexes with different labels or relative motion of each labeled component in motion machines.
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Footnotes
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Reprint requests to: Peixuan Guo, Department of Biomedical Engineering, College of Engineering and College of Medicine, University of Cincinnati, Cincinnati, OH 45221, USA; email: peixuan{at}uc.edu.
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Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.587607.
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- Received March 12, 2007.
- Accepted July 10, 2007.
- Copyright © 2007 RNA Society
