# Quantification of mRNA in Single Cells and Modelling of RT-qPCR Induced Noise

 Title: Quantification of mRNA in Single Cells and Modelling of RT-qPCR Induced Noise Author: Bengtsson, Martin; Rorsman, Patrik; Ståhlberg, Anders; Hemberg, Martin Note: Order does not necessarily reflect citation order of authors. Citation: Bengtsson, Martin, Martin Hemberg, Patrik Rorsman, and Anders Ståhlberg. 2008. Quantification of mRNA in single cells and modelling of RT-qPCR induced noise. BMC Molecular Biology 9:63. Full Text & Related Files: 2483285.pdf (1.327Mb; PDF) Abstract: Background: Gene expression has a strong stochastic element resulting in highly variable mRNA levels between individual cells, even in a seemingly homogeneous cell population. Access to fundamental information about cellular mechanisms, such as correlated gene expression, motivates measurements of multiple genes in individual cells. Quantitative reverse transcription PCR (RT-qPCR) is the most accessible method which provides sufficiently accurate measurements of mRNA in single cells. Results: Low concentration of guanidine thiocyanate was used to fully lyse single pancreatic $$\beta$$-cells followed by RT-qPCR without the need for purification. The accuracy of the measurements was determined by a quantitative noise-model of the reverse transcription and PCR. The noise is insignificant for initial copy numbers >100 while at lower copy numbers the noise intrinsic of the PCR increases sharply, eventually obscuring quantitative measurements. Importantly, the model allows us to determine the RT efficiency without using artificial RNA as a standard. The experimental setup was applied on single endocrine cells, where the technical and biological noise levels were determined. Conclusion: Noise in single-cell RT-qPCR is insignificant compared to biological cell-to-cell variation in mRNA levels for medium and high abundance transcripts. To minimize the technical noise in single-cell RT-qPCR, the mRNA should be analyzed with a single RT reaction, and a single qPCR reaction per gene. Published Version: doi://10.1186/1471-2199-9-63 Other Sources: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2483285/pdf/ Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:10246876 Downloads of this work: