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Published byGabriel Randall Modified over 8 years ago
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Boolean Networks and Experiment Design B-Cell Single Ligand Screen Stuart Johnson Bioinformatics and Data Analysis Lab UCSD
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Outline Why Boolean networks? Building/Displaying Boolean Networks Experiment design Procedure Some competing (sub)networks from the B-Cell data Conclusions
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Why try Boolean Networks? Data noisy partial sampling Model Biochemical system lots of complexity predictive lots of meaning doable forward problem very difficult inverse problem
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Why try Boolean Networks? Boolean data Boolean networks some complexity predictive (exp. design) data-like meaning? consistency = causality; should tell us about connectivity easy
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Boolean data Experimental conditions TIME P-P, 2 nd Msg red=1 at 99% confidence: P(d=NC)<.01 blue=0 everything else 2 nd msg / co-sampled Ca
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Boolean data Experimental conditions TIME P-P, 2 nd Msg red=1 at 99% confidence: P(d=NC)<.01 blue=0 everything else Phosphoproteins
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Boolean data Experimental conditions TIME P-P, 2 nd Msg late resp. Ca -> PP early resp. Ca,cAMP -> No PP groups of siml. resp.
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Boolean data Experimental conditions TIME P-P, 2 nd Msg Node = Full column of data; all exp. cond.
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Known ligand/ receptor interactions from AfCS ligand descriptions Inputs, etc. Experimental Conditions Gq Single ligand screen inputs
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? Extracting patterns Ca (.5 min) ELC LPA AIG Experimental Conditions consistent?
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Graph Time Experimental Conditions displaying and encoding patterns LPA 0 Ca 0.5 ER1 2.5 000 10? 011 110 Truth Table ERK1 (2.5 min)
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all hypotheses: ER1(2.5 min) H1,H2 & H3: Early calcium is associated with ER1 H1: LPA is special (causes an early Ca signal but no ER1) H2: M3A is special (0.5 min Ca, no 1 min Ca, but ER1) H3: no special ligands, ER1 consistent with Ca & cAMP H1 H2 H3
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Constructing complete networks I1I2I3 N1N2N3 573= 105 networks maximum xx Input nodes nodes with truth tables
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Constructing complete networks I1I2I3 N1N2N3
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Constructing complete networks I1I2I3 N1N2N3
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Constructing complete networks I1I2I3 N1N2N3 “Feedback” not allowed! a completely determined network can have multiple output states; forward and inverse problems no longer “easy”
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Experiment Design: networks reproduce results of completed experiments 1 output state All networks: 1 possible output state: For known inputs, every network simply reproduces results of completed experiments (Information) Entropy = score = 0
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Experiment Design: networks are predictive 3 output states All networks: multiple possible output states: these multiple states correspond to unknown entries (?) in truth tables and the different connectivity of the networks Entropy = score > 0
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Dual-ligand experiment design ligand 2 ligand 1 entropy score
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Dual-ligand experiment design ligand 2 ligand 1 entropy score ELC + LPA
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Procedure Build Boolean Networks Do Experiments Display Boolean Networks Score class of experiments pick highest scoring exp.
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Controlling Complexity: Constraint Graphs Graphs specify allowable inputs and hops RCP LIG 2M PP LIG 2M PP LIG 2M PP 1 RCP LIG 2M PP 1
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Graphs specify allowable inputs and hops RCP LIG 2M PP LIG 2M PP LIG 2M PP 1 RCP LIG 2M PP 1 Controlling Complexity: Constraint Graphs
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RCP LIG 2M PP 1 Network display All node rules Can filter/cluster/display these rules to see: ligand classification (chemokines, cytokines, etc) clusters of similar control patterns etc. - “pathways”
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LIG 2M PP Early Calcium vs... Early Calcium + cAMP
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ER1 -> ER2,P90 LIG 2M PP 1 P90 -> AKT ST6 -> ST3
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RCP LIG 2M PP Early Ca & Gq control vs... Early Ca & G12
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Conclusions This is a general method/implementation and will extend to the RAW screens and FXM in some form Boolean network analysis has many interesting features: –learns from experiments/proposes new exp. –formalizes inclusion of known information as either constraint graphs or hidden nodes –caveat 1: the BN have encoded any real meaning –caveat 2: you can control complexity and digest the networks inferred http://dev.afcs.org:12057/ for the latest results, navigable/clickable networks and more backgroundhttp://dev.afcs.org:12057/
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