- 8 -
Section 4: Network Visualization using R and Cytoscape – An example
We provide two options for visualizing the changes in associations between a
protein/microRNA hub and its interactors. Typically, the input file for data visualization
will correspond to the output correlation file generated by the function
identifySignificantHu s (Section 3). For example, if the user was interested in visualizing
the hub-interactor correlations corresponding to the analysis performed in Example 1 of
Section 3, then the input file will be Test_Output_PPI_Cor.txt. However, to illustrate our
data visualization function, we consider input files that are already available in the
Example dataset (Section 2).
Option 1: Visualization in R
For an analysis involving two conditions, we can visualise a single hub of interest
together with its interactors, e.g. the gene “ABL1” along with its interactors, by typing at
the R command prompt
visualizeNetwork(inputFile="Gene_Output_1_Cor.txt"
, inputHub="ABL1"
, paletteVector=c("red", "yellow", "green"))
For an explanation of the data file to be provided as input, refer Section 9. Similarly, for
an example visualization of a microRNA and its interactome, at the R command prompt
type
visualizeNetwork(inputFile="Micro_Output_1_Cor.txt"
, inputHub="hsa-miR-551a"
, paletteVector=c("red", "yellow", "green"))
For an analysis involving multiple conditions, we can visualise a single hub of interest
together with its interactors for exactly two conditions, e.g. the gene “ABL1” along with
its interactors in States B and C, by typing at the R command prompt
visualizeNetwork(inputFile="Gene_Output_2_Cor.txt"
, inputHub="ABL1"
, paletteVector=c("red", "yellow", "green")
, condVector = c("StateB", "StateC"))
Option 2: Visualization in Cytoscape
For visualization in Cytoscape, we can use (i) the output file containing the hub-
interactor pairs or (ii) a subset of this file. The advantage of using the subset is that it
allows us to focus on only the significant hubs. To obtain the subset, at the R command
prompt type