Proteomics of Xenopus development.

Modern mass spectrometry-based methods provide an exciting opportunity to characterize protein expression in the developing embryo. We have employed an isotopic labeling technology to quantify the expression dynamics of nearly 6000 proteins across six stages of development in Xenopus laevis from the single stage zygote through the mid-blastula transition and the onset of organogenesis. Approximately 40% of the proteins show significant changes in expression across the development stages. The expression changes for these proteins naturally falls into six clusters corresponding to major events that mark early Xenopus development. A subset of experiments in this study have quantified protein expression differences between single embryos at the same stage of development, showing that, within experimental error, embryos at the same developmental stage have identical protein expression levels.