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Metodi post-genomici in biochimica cellulare. Metodi post-genomici. Metodi post-genomici. Quantitative analysis of systems biology by taking advantage of available genomic information at the level of SNPs analysis associated to disease or drug response mRNA (transcriptomics)
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Metodi post-genomici • Quantitative analysis of systems biology by taking advantage of available genomic information at the level of • SNPs analysis associated to disease or drug response • mRNA (transcriptomics) • Protein (proteomics) • Post-translational modifications (aka “modificomics”) • Surface exposure (surfomics) • Protein-protein interactions (interactomics) • Small metabolites (metabolomics) and their relations (metabonomics) Manyother fantasy exercises (glycomics, lipidomics, allergenomics, degradomics, excluding – perhaps – comics...) G.B Smejkal, “I’m an –omics, you’re an -omics... ” Exp. Rev. Proteomics 3 (2006) 383-385
Metodi post-genomici • Modelli cellulari e animali • Trascrittomica • Proteomica • Systems biology
Modelli cellulari(farmacologici e/o genetici) • Facilità di mantenimento e trattamento • Possibilità di combinare trattamento farmacologico e manipolazione genetica • Utili per riprodurre un singolo meccanismo • Cellule umane (o murine)
Modelli animali(farmacologici) • Intero organismo vs. cellule isolate • Trattamento sistemico o lesione chimica locale • Possibilità di valutare l’effetto anterogrado/retrogrado
Modelli animali (e vegetali?!?)(genetici) • Organismi modello • Genoma noto • Non solo topo! • Vita breve • Invertebrati (e piante…)
Trascrittomica • Distanza Euclidea • Correlazione di Pearson
Proteomica • Non c’è correlazione tra quantità di mRNA e quantità di proteina (Gygi et al., 1999) • Il proteoma è un’istantanea del fenotipo a livello biochimico • Il proteoma tiene conto del processing delle proteine S.P.Gygiet al., Mol. Cell. Biol.19, 1720 (1999)
Proteomica • Metodi basati su 2-DE • Metodi “gel-free”
Vantaggi • Possibilità di caricare campioni non purificati • Risoluzione estremamente alta • I gel 2 –DE sono collettori di frazioni proteiche molto efficienti • Proteine sono protette all’interno della matrice del gel Problematiche • Gradiente di pH • Limiti nel determinare proteine poco rappresentate • Capacità di caricare campione • Proteine idrofobiche • Proteine ad alto peso molecolare Proteomica (2-DE)
Proteomica (2-DE) • A global, unbiased approach • Hypothesis-generating rather than hypothesis-driven • A “find the difference” game between two conditions Control Treated
Proteomica (2-DE) Francesca Marco Giovanni Maria
Proteomica (2-DE) Proteine Colorazione Acquisizione Analisi di immagine
Proteomica (2-DE) Find the difference… Controllo Esordio Precoce Esordio Tardivo
Proteomica (2-DE) Find the difference…
Proteomica (2-DE) Metodi statistici
Proteomica (2-DE) Identificazione delle proteine • Peptide mass fingerprinting • LC-MS/MS • Western blot (non globale)
Proteomica (2-DE) Peptide Mass Fingerprinting
Proteomica (2-DE) Peptide Mass Fingerprinting
Proteomica (2-DE) Peptide Mass Fingerprinting (Limiti) • La proteina non è presente nel database • La proteina è ricca di modificazioni co/post-traduzionali • Lo spot nasconde più di una proteina
Proteomica (2-DE) Peptide Mass Fingerprinting (Limiti) • La proteina non è presente nel database • La proteina è ricca di modificazioni co/post-traduzionali • Lo spot nasconde più di una proteina
Proteomica (2-DE) LC-MS/MS
Differential in-gel electrophoresis (DIGE) • Matching not needed • Spatially accurate • Sensitive to small quantitative changes • High cost • Weak signal • Only binary comparison
DIGE Control [Cy5]Pharmacological Treatment [Cy3]
Gel-basedvs.Gel-free Webb-Robertson and Cannon, Brief Bioinform 2007;8:304-317. • Poor detection of acidic- basic- proteins • poor solubility of membrane proteins • limited loading capacity of gradient pH strips (crowding effect) • Low reproducibility of gels • relatively low throughput • 2D gels perform robust separations • 2D gels are well-suited for PTM analysis • Parallel, quantitative and label-free readout Monteoliva and Albar, BRIEFINGS IN FUNCTIONAL GENOMICS AND PROTEOMICS. VOL 3. NO 3. 220–239. Proteins do the job, not peptides
Proteomica (gel-free) • Metodi quantitativi (ICAT, iTRAQ, …) • Protein arrays
Quantitative Proteomics • Labelling (ICAT, iTRAQ, SILAC, 18O enrichment, …) • Label free (AQUA, SRM/MRM, …)
IsobaricTaggingfor Relative and AbsoluteQuantitation (iTRAQ)
Proteomica (gel-free) • Protein arrays (e SELDI)
What next? • You will call your preferred MS expert to ask her/him to identify your spots • You will get a list of protein names • What tells you that list?
Systems Biology • Necessità di analizzare un elevato numero di informazioni (Network analysis) • Necessità di arricchire un ridotto numero di informazioni (Network enrichment)
Systems Biology • Interazione fisica • Stesso pathway (KEGG) • Stessa Gene Ontology (GO)
Protein Networks • Cellular processes are regulated by protein interaction networks • Protein networks: • control development programs • regulate signal transduction pathways • manage metabolic pathways • are based on physical interactions or cellular localization
Protein networks Graph: a graphical representation of elements (nodes) connected by edges. Nodes are proteins, edges are interactions
Protein networks Hub: connecting several nodes Subnetwork
Protein networks Regulating interactions: Controls Inhibits Feedback Interacts with…
Building protein networks • Co-occurrence in databases • Physical interactions • Genomic proximity • Expression • Proteomics • Literature (pubmed) • Pathways (KEGG, Reactome, …) • GO Terms
Available Databases • • Free, online PPI data • – IntACT (EBI) http://www.ebi.ac.uk/intact/ • – DIP http://dip.doe‐mbi.ucla.edu/dip/Main.cgi • – MINT http://mint.bio.uniroma2.it/mint/Welcome.do • – BIND/BOND http://bond.unleashedinformatics.com/ • – HPID http://wilab.inha.ac.kr/hpid/ • – UniProt http://www.uniprot.org/ • – NCBI Entrez Gene http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene • • Pathways • – Reactome http://www.reactome.org/ • – KEGG http://www.genome.jp/kegg/pathway.html • – Panther http://www.pantherdb.org/pathway/ • – NCI Nature PathwayInteractionDb http://pid.nci.nih.gov/ • – BioPATH http://www.molecular‐networks.com/biopath/index.html • • Commercial applications • – GeneGO, Ingenuity Pathway Analysis…