title: Single-Cell Mass Spectrometry for Discovery Proteomics: Quantifying Translational Cell Heterogeneity in the 16-Cell Frog (Xenopus) Embryo.
abstract: We advance mass spectrometry from a cell population-averaging tool to one capable of quantifying the expression of diverse proteins in single embryonic cells. Our instrument combines capillary electrophoresis (CE), electrospray ionization, and a tribrid ultrahigh-resolution mass spectrometer (HRMS) to enable untargeted (discovery) proteomics with ca. 25 amol lower limit of detection. CE-μESI-HRMS enabled the identification of 500-800 nonredundant protein groups by measuring 20 ng, or <0.2% of the total protein content in single blastomeres that were isolated from the 16-cell frog (Xenopus laevis) embryo, amounting to a total of 1709 protein groups identified between n=3 biological replicates. By quantifying ≈150 nonredundant protein groups between all blastomeres and replicate measurements, we found significant translational cell heterogeneity along multiple axes of the embryo at this very early stage of development when the transcriptional program of the embryo has yet to begin.
authors.affiliation: Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, 800 22ndStreet, NW, Suite 4000, Washington, DC, 20052, USA.
authors.forename: Camille
authors.initials: C
authors.lastname: Lombard-Banek
authors.affiliation: Department of Anatomy and Regenerative Biology, The George Washington University, Washington, DC, 20052, USA.
authors.forename: Sally A
authors.initials: SA
authors.lastname: Moody
authors.affiliation: Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, 800 22ndStreet, NW, Suite 4000, Washington, DC, 20052, USA. petern@gwu.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Nemes
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000166:cytology*; D040901:Proteomics; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014981:Xenopus / Q000196:embryology*
keywords: Xenopus laevis; embryo; mass spectrometry; proteins; single-cell studies