In this example we investigate the ENCODE Chip-Seq narrow and broad data, extracted from the GMQL remote repository to automate all the steps needed to identify transcription factor (TF) high accumulation DNA zones using RGQML together with TFHAZ, another R/Bioconductor package . The knowledge of DNA regions in which transcription factors bind, in particular the HOT (High Occupancy Target) regions occupied by many different factors, is crucial to understand cancer genesis and develop new targeted therapies.
Load the RGMQL package and initialize the remote GMQL context of scalable data management engine, specifying remote_processing = TRUE, and, possibly, an authenticated login:
library(RGMQL)
## Caricamento del pacchetto richiesto: RGMQLlib
## GMQL successfully loaded
remote_url <- "http://www.gmql.eu/gmql-rest"
init_gmql(url = remote_url, remote_processing = TRUE) #, username = 'XXXX', password = 'XXXX')
## [1] "your Token is b0fbf303-4693-4091-9e12-7c4613c2fd66"
Download and extract the list of datasets in the curated remote repository and focus on those concerning ENCODE:
dataset_list <- show_datasets_list(remote_url)
list <- unlist(lapply(dataset_list[["datasets"]], function(x) x$name))
grep(pattern = 'ENCODE', x = list, value = TRUE)
## [1] "GRCh38_ANNOTATION_GENCODE" "GRCh38_ENCODE_BROAD_2019_01"
## [3] "GRCh38_ENCODE_BROAD_2019_07" "GRCh38_ENCODE_BROAD_2020_01"
## [5] "GRCh38_ENCODE_BROAD_AUG_2017" "GRCh38_ENCODE_BROAD_NOV_2017"
## [7] "GRCh38_ENCODE_NARROW_2019_01" "GRCh38_ENCODE_NARROW_2019_07"
## [9] "GRCh38_ENCODE_NARROW_2020_01" "GRCh38_ENCODE_NARROW_AUG_2017"
## [11] "GRCh38_ENCODE_NARROW_NOV_2017" "HG19_ANNOTATION_GENCODE"
## [13] "HG19_ENCODE_BROAD_2019_01" "HG19_ENCODE_BROAD_AUG_2017"
## [15] "HG19_ENCODE_BROAD_NOV_2016" "HG19_ENCODE_BROAD_NOV_2017"
## [17] "HG19_ENCODE_NARROW_2019_01" "HG19_ENCODE_NARROW_AUG_2017"
## [19] "HG19_ENCODE_NARROW_NOV_2016" "HG19_ENCODE_NARROW_NOV_2017"
Select ChIP-seq data from the ENCODE NARROW dataset AUG_2017, aligned to HG19:
Enc_Narrow <- read_gmql("public.HG19_ENCODE_NARROW_AUG_2017",
is_local = FALSE)
HM_TF_rep_narrow <- filter(Enc_Narrow, assay == "ChIP-seq" & assembly
== "hg19" & project == "ENCODE" & file_status == "released" & biosample_term_name == "H1-hESC" & output_type == "optimal idr thresholded peaks")
Select ChIP-seq data from the latest ENCODE BROAD dataset AUG_2017, aligned to HG19 and:
Enc_Broad <- read_gmql("public.HG19_ENCODE_BROAD_AUG_2017",
is_local = FALSE)
HM_TF_rep_broad <- filter(Enc_Broad, assay == "ChIP-seq" & assembly ==
"hg19" & project == "ENCODE" & file_status ==
"released" & biosample_term_name == "H1-hESC" & output_type == "optimal idr thresholded peaks")
Take the union of the two previously generated datasets:
HM_TF_rep <- union(HM_TF_rep_broad, HM_TF_rep_narrow)
Filter out samples subjected to pharmacological treatment or with specific “audit” marker:
HM_TF_rep_good_0 <- filter(HM_TF_rep, !biosample_treatments == "*" & !
(audit_error == "extremely low read depth" | audit_error == "extremely low read
length") & !(audit_warning == "insufficient read depth") & !(audit_not_compliant ==
"insufficient read depth" | audit_not_compliant =="insufficient replicate concordance" | audit_not_compliant == "missing input
control" | audit_not_compliant == "severe bottlenecking" | audit_not_compliant
== "unreplicated experiment"))
Filter out samples related to HM histone modifications:
TF_rep_good_0 <- filter(HM_TF_rep_good_0, !(experiment_target == "H2AFZhuman" | experiment_target == "H3F3A-human" | experiment_target == "H3K27ac-human" | experiment_target == "H3K27me3-human" | experiment_target == "H3K36me3-human" | experiment_target == "H3K4me1-human" | experiment_target == "H3K4me2-human" | experiment_target == "H3K4me3-human" | experiment_target == "H3K79me2-human" | experiment_target == "H3K9ac-human" | experiment_target == "H3K9me1-human" | experiment_target == "H3K9me2-human" | experiment_target == "H3K9me3-human" | experiment_target == "H4K20me1-human"))
Create new regions attribute: Length of each region and for each sample, compute the number of regions and the sum of each region length just created:
TF_rep_good_1 <- select(TF_rep_good_0, regions_update = list(length = right - left))
TF_rep_good <- extend(TF_rep_good_1, Region_number = COUNT(),
sum_length = SUM("length"))
TF_rep_good_merged <- aggregate(TF_rep_good, groupBy =
conds(default = c("biosample_term_name")))
TF_rep_good_ordered <- arrange(TF_rep_good_merged,
regions_ordering = list(ASC("length")))
collect(TF_rep_good_ordered, name = "TF_rep_good_ordered")
job <- execute()
(1.1)Monitor the job status:
trace_job(remote_url , job$id)
dataset_name <- job$datasets[[1]]$name
print(dataset_name)
grl_TF_rep_good_ordered <- download_as_GRangesList(remote_url, dataset_name)
download_dataset(remote_url, datasetName = dataset_name, path = './Results_use_case_3')
name_sample <- names(grl_TF_rep_good_ordered)# campione singolo
g <- grl_TF_rep_good_ordered[[name_sample]] #estraggo GRanges
Region_number_tot <- length(g) # conto tutte le regioni
n_up <- Region_number_tot * 0.95 #95percentile del numero di regioni
n_up_1 <- n_up + 1
index <- which(g$order >= ceiling(n_up) & g$order <= floor(n_up_1))
region <- g[index]
threshold <- region$length
threshold <- as.numeric(threshold)
threshold
## [1] 1147
Going back to RGQML remote processing, take only the regions with region lengths greater than 100 and smaller than the threshold:
TF_rep_good_filtered_0 <- filter(TF_rep_good, r_predicate = length >= 100 & length <= threshold)
Create new metadata for each sample, with number of filtered regions and the sum of their lengths:
TF_rep_good_filtered <- extend(TF_rep_good_filtered_0,
Region_number_filtered = COUNT(),
sum_length_filtered = SUM("length"))
Combine multiple replicate samples of the same TF experiment:
TF_0 <- cover(TF_rep_good_filtered, 1, ANY(), groupBy =
conds("experiment_target"))
Add new region attribute as length of each region after sample combination:
TF_1 <- select(TF_0, regions_update = list(length = right - left))
Create new metadata for each sample, with number of combined regions, and min, max and sum of their lengths:
TF <- extend(TF_1, Region_number_cover = COUNT(), sum_length_cover =
SUM("length"), min_length_cover = MIN("length"), max_length_cover = MAX("length"))
Materialize TF dataset into repository and download it on mass memory but also in main memory as GRangesList
collect(TF, name= "TF_res")
res <- execute()
#Monitor job status:
trace_job(remote_url, res$id)
# Download dataset as folder:
res_name <- res$datasets[[1]]$name
download_dataset(remote_url, res_name, path = './Results_use_case_3')
# Download dataset as GRangesList:
samples <- download_as_GRangesList(remote_url, res_name)
Post-processing before the analysis with TFHAZ
TF=vector()
len_rep <- sapply(samples, function(x) len <- length(x))
TF_rep <- mapply(function(x, l){
exp <- x$experiment_target
TF_temp <- rep(exp, l)
TF <- append(TF, TF_temp)
}, samples@metadata, len_rep) #metadata(samples)
TF <- unlist(TF_rep)
H1_hESC <- unlist(samples)
data <- data.frame(H1_hESC, TF)
H1_hESC <- as(data, "GRanges")
After loading the TFHAZ package, find the transcription factor HOT DNA zones focusing on one chromosome at at time, by executing the following instructions:
library(TFHAZ)
TF_acc_21_w_0 <- accumulation(H1_hESC, "TF", "chr21", 0)
d_zones <- high_accumulation_zones(TF_acc_21_w_0, method =
"overlaps", threshold = "std")
print(d_zones)
## $zones
## GRanges object with 1300 ranges and 0 metadata columns:
## seqnames ranges strand
## <Rle> <IRanges> <Rle>
## [1] chr21 9545017-9545326 *
## [2] chr21 9857474-9857783 *
## [3] chr21 9902931-9903240 *
## [4] chr21 9911648-9912212 *
## [5] chr21 9913190-9913499 *
## ... ... ... ...
## [1296] chr21 47877820-47879306 *
## [1297] chr21 48017969-48018244 *
## [1298] chr21 48045673-48046188 *
## [1299] chr21 48055000-48056276 *
## [1300] chr21 48087336-48088510 *
## -------
## seqinfo: 1 sequence from an unspecified genome; no seqlengths
##
## $n_zones
## [1] 1300
##
## $n_bases
## [1] 746512
##
## $lengths
## TH n_zones length_zone_min length_zone_max
## 23198.0000 1300.0000 100.0000 19655.0000
## length_zone_mean length_zone_median length_zone_sd
## 574.2400 400.0000 728.5139
##
## $distances
## TH n_zones dist_zone_min dist_zone_max
## 23198.00 1300.00 3.00 4244193.00
## dist_zone_mean dist_zone_median dist_zone_sd
## 29097.98 8477.00 129112.99
##
## $TH
## [1] 23198
##
## $chr
## [1] "chr21"
##
## $w
## [1] 0
##
## $acctype
## [1] "TF"
Log out from remote engine:
logout_gmql(remote_url)
## [1] "Logout"