Supporting script to create a cell cycle subset from STRING data. Used for FND-MAT-Graphs_and_networks deliverables

scripts/ABC-makeScCCnet.R

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+# ABC-makeScCCnet.R
+#
+# Create a subnetwork of high-confidence yeast genes with a "mitotic cell cycle"
+# GOSlim annotation.
+#
+# Boris Steipe for ABC learning units
+#
+# Notes:
+#      STRING data source:
+#        Download page: https://string-db.org/cgi/download.pl?species_text=Saccharomyces+cerevisiae
+#        Data: (20.8 mb) https://string-db.org/download/protein.links.full.v10.5/4932.protein.links.full.v10.5.txt.gz
+#
+#      GOSlim data source:
+#        Info page: http://www.geneontology.org/page/go-slim-and-subset-guide
+#        Data: (3 mb) https://downloads.yeastgenome.org/curation/literature/go_slim_mapping.tab
+#
+#
+# Version:  1.0
+#
+# Date:     2017  10  06
+# Author:   Boris Steipe (boris.steipe@utoronto.ca)
+#
+# Versions:
+#           1.0    First code copied from 2016 material.
+#
+# TODO:
+#
+#
+# ==============================================================================
+
+if (!require(readr, quietly = TRUE)) {
+  install.packages("readr")
+  library(readr)
+}
+
+
+# STRING functional interaction data
+
+# Read STRING Data (needs to be downloaded from database, see URL in Notes)
+STR <- read_delim("./data/4932.protein.links.full.v10.5.txt", delim = " ")
+
+# Subset only IDs and combined_score column
+STR <- STR[ , c("protein1", "protein2", "combined_score")]
+
+# head(STR)
+# sum(STR$combined_score > 909)  # 100270 edges
+# subset for 100,000 highest confidence edges
+STR <- STR[(STR$combined_score > 909), ]
+
+# IDs are formatted like 4932.YAL005C ... drop the "4932." prefix
+STR$protein1 <- gsub("^4932\\.", "", STR$protein1)
+STR$protein2 <- gsub("^4932\\.", "", STR$protein2)
+# head(STR)
+
+# get a vector of gene names in this list
+myIntxGenes <- unique(c(STR$protein1, STR$protein2))  # yeast systematic gene
+                                                      # names
+
+
+# GOSlim functional annotations
+#
+# Read GOSlim data  (needs to be downloaded from database, see URL in Notes)
+
+Gsl <- read_tsv("./data/go_slim_mapping.tab",
+                col_names = c("ID",
+                              "name",
+                              "SGDId",
+                              "Ontology",
+                              "termName",
+                              "termID",
+                              "status"))
+
+# head(Gsl)
+#
+# What cell cycle names does it contain?
+# myGslTermNames <- unique(Gsl$termName)  # 169 unique terms
+# myGslTermNames[grep("cycle", myGslTermNames)]
+# [1] "regulation of cell cycle"  "mitotic cell cycle"  "meiotic cell cycle"
+#
+# Choose "mitotic cell cycle" as the GOslim term to subset with
+#
+
+scCCgenes <- unique(Gsl$ID[Gsl$termName == "mitotic cell cycle"])
+# length(scCCgenes)  # 324 genes annotated to that term
+
+# sum(scCCgenes %in% myIntxGenes)  # 294 of these have high-confidence
+#                                     # interactions
+
+# Define scCCnet ... the S. Cervisiae Cell Cycle network
+# Subset all rows for which BOTH genes are in the GOslim cell cycle set
+scCCnet <- STR[(STR$protein1 %in% scCCgenes) &
+               (STR$protein2 %in% scCCgenes), ]
+
+# How many genes are there?
+# length(unique(c(scCCnet$protein1, scCCnet$protein2)))  #261
+
+# Each edge is listed twice - now remove duplicates.
+#
+# Step 1: make a vector: sort two names so the frist one is alphabetically
+#         smaller han the second one. This brings the two names into a defined
+#         order. Then concatenate them with a "." - the resulting string
+#         is always the same, for any order. E.g. c("A", "B") gives "A.B"
+#         and c("B", "A") also gives "A.B". This identifies duplicates.
+
+x <- apply(cbind(scCCnet$protein1,
+                 scCCnet$protein2),
+           1,
+           FUN = function(x) { return(paste(sort(x), collapse = ".")) })
+# head(x) # "YAL016W.YGR040W" "YAL016W.YOR014W" "YAL016W.YDL188C" ... etc.
+
+# sum(duplicated(x))  # 1280
+
+# Step 2: drop all rows that contain duplicates in x
+scCCnet <- scCCnet[! duplicated(x), ]
+
+# Confirm we didn't loose genes
+# length(unique(c(mySubnet$protein1, mySubnet$protein2)))  # 261, no change
+# Network has 261 nodes, 1280 edges
+
+save(scCCnet, file = "./data/scCCnet.RData")
+
+# load("./data/scCCnet.RData")   # <<<- use this to load the object when
+                                 # needed
+
+
+# [END]