title: Digital quantification of gene expression using emulsion PCR.
abstract: Here we describe a single-molecule quantitative assay of mRNA levels based on mRNA mediate-ligation and BEAMing (beads, emulsion, amplification, and magnetics) technique, which allows accurate and parallel measurement of multiple genes from a small amount of cells. In this method, a pair of oligos complementary target mRNA was used to probe transcripts for each gene of interest. The ligated products of oligos pair were clonally amplified on beads in millions of parallel compartmentalized droplets in a water-in-oil emulsion. The levels of each transcript within a sample were measured by counting the number of the correspondingly amplified beads which were immobilized on a glass surface. To demonstrate its utility, this method has been applied to the quantitation of the mRNA levels for two transcription factors, Klf4 and Sox5, and a housekeeping gene, Gapdh, in human leukemia K562 cells before and after induction with phorbol 12-myristate 13-acetate. Interestingly, we found a significant downregulation of the mRNA level of Sox5 after phorbol 12-myristate 13-acetate treatment. The mRNA mediate-ligation and BEAMing technique provides an accurate and sensitive way to quantify the amount of multiple specific mRNA in a very small number of cells, which may be valuable in the studies requiring precise and parallel quantization of multiple mRNA in the defined cell populations.
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing, PR China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Shi
authors.forename: Chao
authors.initials: C
authors.lastname: Tang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Dequan
authors.initials: D
authors.lastname: Zhou
authors.forename: Zuhong
authors.initials: Z
authors.lastname: Lu
mesh_terms: D045744:Cell Line, Tumor; D004655:Emulsions; D020869:Gene Expression Profiling / Q000379:methods*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D055755:SOXD Transcription Factors / Q000235:genetics / Q000378:metabolism; D012680:Sensitivity and Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D004655:Emulsions; C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D012333:RNA, Messenger; D055755:SOXD Transcription Factors; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D013755:Tetradecanoylphorbol Acetate