Proteomics of early zebrafish embryos.
Ontology highlight
ABSTRACT: Background
Zebrafish (D. rerio) has become a powerful and widely used model system for the analysis of vertebrate embryogenesis and organ development. While genetic methods are readily available in zebrafish, protocols for two dimensional (2D) gel electrophoresis and proteomics have yet to be developed.Results
As a prerequisite to carry out proteomic experiments with early zebrafish embryos, we developed a method to efficiently remove the yolk from large batches of embryos. This method enabled high resolution 2D gel electrophoresis and improved Western blotting considerably. Here, we provide detailed protocols for proteomics in zebrafish from sample preparation to mass spectrometry (MS), including a comparison of databases for MS identification of zebrafish proteins.Conclusion
The provided protocols for proteomic analysis of early embryos enable research to be taken in novel directions in embryogenesis.
SUBMITTER: Link V
PROVIDER: S-EPMC1363346 | biostudies-literature | 2006 Jan
REPOSITORIES: biostudies-literature
Publications
Proteomics of early zebrafish embryos.
Link Vinzenz V Shevchenko Andrej A Heisenberg Carl-Philipp CP
BMC developmental biology 20060113
<h4>Background</h4>Zebrafish (D. rerio) has become a powerful and widely used model system for the analysis of vertebrate embryogenesis and organ development. While genetic methods are readily available in zebrafish, protocols for two dimensional (2D) gel electrophoresis and proteomics have yet to be developed.<h4>Results</h4>As a prerequisite to carry out proteomic experiments with early zebrafish embryos, we developed a method to efficiently remove the yolk from large batches of embryos. This ...[more]
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Project description:Sample Preparation | Four biological replicate of 25 dechorionated, but non-deyolked, zebrafish embryos were collected at 4 time points of embryonic development: 1-cell stage (0-hpf, hour post fertilization), 2-hph, 4-hpf, and 6-hpf. All 16 pooled embryo samples were lysed independently by adding 100 ul of Mammalian lysis buffer and 1x Protease Inhibitor cocktail.
Digestion | Samples were reduced and alkylated with TCEP and 2-chloroacetamide. Six volumes of pre-chilled acetone were added, and the precipitation was let to proceed overnight. The precipitated proteins were dissolved in 100 ul of 50 mM TEAB, mass spectrometry grade trypsin (Promega Gold) was added at 1:40 w/w and the digestion was let to proceed at 37oC overnight. Pierce fluorometric peptide assay was performed on 10 ul of each digested sample.
Tandem Mass Tag (TMT) Labeling | 20 ul of anhydrous acetonitrile were added to each of the 0.5mg TMTpro 16plex reagents. For each sample, 20 ug of peptides were measured out and adjusted to 100 ul with 100 mM TEAB, then mixed with the TMT reagents. The replicate samples for each of the time points were labeled for 1 hr with TMTpro-126, 127N, 127C, -128N (0-hpf, replicates 1-4); 128C, 129N, 129C, 130C (2-hpf, 1-4); 130C, 131N, 131C, 132N (4-hpf, 1-4), 132C, 133N, 133C, 134N (6-hpf, 1-4), respectively. After checking labeling efficiency (>99%), 30 ul each of the 16 differentially labeled samples were combined in a new tube and the resulting volume was reduced using a SpeedVac concentrator to less than 10 ul.
High pH Reverse Phase Fractionation | 300 ul of the TMT-labeled peptide mixture (in 0.1% TFA) were loaded onto a Pierce high pH fractionation cartridge placed on a 2.0 ml sample tube. After centrifuging at 3000 x g for 2 minutes, the eluate was collected as the flow-through fraction. The loaded cartridge was placed on a new sample tube, washed with 300 ul of ddH20, and the eluate collected as wash fraction. An additional round of washing was performed using 300 ul of 5% acetonitrile in 0.1% TFA to remove unreacted TMT reagent. A total of 9 HpH RP fractions (E1-E9) were collected by sequential elution in new sample tubes using 300 ul of 10%, 12.5%, 15%, 17.5%, 20%, 22.5%, 25%, 50%, and 80% acetonitrile in 0.1% TFA. Dried samples were resolubilized in 44 ul of buffer A (5% acetonitrile in 0.1% formic acid, FA) before LC-MS analysis.
Multiplexed Mass Spectrometry Analysis | TMT-labeled peptides were analyzed on an Orbitrap Eclipse Tribrid Mass Spectrometer with a FAIMS Pro interface, equipped with a Nanospray Flex Ion Source, and coupled to a Dionex UltiMate 3000 RSCLnano System. Peptides were loaded on an Acclaim PepMap 100 C18 trap cartridge (0.3 mm i.d., 5 mm length) with the U3000 loading pump via the autosampler. A 75 um i.d. analytical microcapillary column was packed in-house with 250 mm of 1.9 um ReproSil-Pur C18-AQ resin (Dr. Masch). The Orbitrap Eclipse was set up to run the TMT-SPS-MS3 method with three FAIMS compensation voltages (CV) at -40V, -55V, and -70V and a cycle time of 1 sec. Briefly, peptides were scanned from 400-1600 m/z in the Orbitrap at 120,000 resolving power before MS2 fragmentation by CID at 35% NCE and detection in the ion trap set to turbo detection. Dynamic exclusion was enabled for 45s. Real time search (RTS) was performed during the ddMS2 IT CID step against a non-redundant Danio rerio sequence database downloaded from UniProtKB 2021-03 and complemented with common contaminants. Carbamidomethyl and TMTpro16plex (304.2071 Da on Kn) were searched statically, while methionine oxidation was searched as a variable modification. Synchronous precursor scanning (SPS) selected the top 10 MS2 peptides for TMT reporter ion detection in the Orbitrap using HCD fragmentation at 65% NCE at 50,000 resolving power. In addition, RTS was also set up to reject further fragmentation of peptides mapping to contaminants and yolk proteins using an exclusion list with the keywords Contaminant, Phosvitin, and Vitellogenin.
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