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Quy Nguyen and Nora Kabbara 06 March 2014. Background. How genetic information results in gene products? Human disease exceed number of genes. Disorder based on polygenetic traits. Number of human genes does not differ from other less complex organisms.
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QuyNguyen and Nora Kabbara 06 March 2014
Background • How genetic information results in gene products? • Human disease exceed number of genes. • Disorder based on polygenetic traits. • Number of human genes does not differ from other less complex organisms. • C. elegans vs. Humans---> Almost same number of genes yet drastic difference in complexity • Most cellular processes carried out by multiprotein complex. • Use haploid S. cerevisiae (baker’s yeast) to perform comprehensive protein analysis
Methods • Tandem-affinity purification (TAP) • TAP cassette inserted into C terminus of yeast ORF • Generate TAP-tagged fusion protein for purification.
Methods • TAP • TAP Cassette consist of • CBP tag, TEV cleave site, ProtA • Multi-steps purification to yield pure samples under native conditions. Puig, O. et. al. 2001
Methods • Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) • Mass spectrometry for identification of biomolecules that is fragile to conventional ionization. Lewis, K. et. al. 2000
Results • Multiple distinct tags for the protein complex to identify key components. • Identified key subunit (Tpd3) and looked for what other proteins interacted with it. Polyadenylationmachinery complex used as entry point for purification
Results • Understanding integration and coordination of cellular functions. • Different colors show different proteins involved in cellular functions(ex. red for cell cycle, violet energy metabolism).There are even more connections yet to be discovered.
Conclusion • Assign cellular function to new or nonannotated gene products. • Largest analysis of protein complex to date. • TAP can purify complexes from different cellular compartments. • Identification of low-abundance proteins. • Purification of large complex. • Group cellular protein into complexes. • Provide molecular context for choice evaluation of drug targets.