annotateU12: Annotate the U12 (and U2) type introns

In gacatag/IntEREst: Intron-Exon Retention Estimator

Annotate the U12 (and U2) type introns

Description

Receives coordinates, a reference genome and PWMs of splice site of U12 and U2 type introns, and returns a data.frame with 2 columns. The first column shows wheather the corresponding sequences matches U12, U2 or both (U12/U2) consensus sequences (based on their score when fitting the PWMs). The second column shows whether the match is on positive strand or negative when fitting the PWMs to the sequences.

Usage

annotateU12(pwmU12U2=c(), pwmSsIndex=c(), referenceChr, referenceBegin, 
	referenceEnd, referenceIntronExon, intronExon='intron', 
	matchWindowRelativeUpstreamPos=c() , matchWindowRelativeDownstreamPos=c(), 
	minMatchScore='80%', refGenome='', setNaAs='U2', annotateU12Subtype=TRUE, 
	includeMatchScores=FALSE, ignoreHybrid=TRUE, filterReference)

Arguments

pwmU12U2	A list containing position weight matrices of (in order): Donor site, branch point, and acceptor site of U12-type introns, and donor site and acceptor site of U2-type introns. If not provided, the information related to pwmU12db data is used.
pwmSsIndex	A list (or vector) that contains the column number in each element of pwmU12U2 that represents the 5' or 3' Splice Site; The order should be equivalent to the pwmU12U2. If not provided the information from pwmU12db data is used, i.e. pwmSsIndex=list(indexDonU12=1, indexBpU12=1, indexAccU12=3, indexDonU2=1, indexAccU2=3)
referenceChr	Chromosome names of the references (e.g. introns).
referenceBegin	A vector that corresponds to the begin coordinates of the reference (e.g. introns).
referenceEnd	A vector that corresponds to the end coordinates of the reference (e.g. introns). referenceEnd should be greater than or equal to referenceBegin.
referenceIntronExon	A vector with the same size as the referenceChr, referenceBegin and referenceEnd which contains 'intron' and 'exon' describing what (either intron or exon) each element of the 3 vectors represents.
intronExon	Should be assigned either 'intron' or 'exon' or c('intron','exon') based on whether match the PWM to the intronic, exonic, or intronic and exonic regions of the reference. By default it seeks matches in intronic regions (intronExon='intron').
matchWindowRelativeUpstreamPos	A vector the same size as the pwmU12U2 (and the same order of donor/acceptor sites' information in pwmU12U2) which consists of the upstream distance from the donor/acceptor site from which each PWM should be tested (to see if they match). If not provided, the information from pwmU12db data is used i.e. matchWindowRelativeUpstreamPos= c(NA, -29, NA, NA, NA).
matchWindowRelativeDownstreamPos	A vector the same size as the pwmU12U2 (and the same order of donor/acceptor sites' information in pwmU12U2) which consists of the downstream distance from the donor/acceptor site to which each PWM should be tested (to see if they match). If not provided, the information from pwmU12db data is used i.e. matchWindowRelativeDownstreamPos= c(NA,-9, NA, NA, NA).
minMatchScore	Min percentage match score, when scoring matching of a sequence to pwm. Different score thresholds could also be defined for the various sites (U12/U2 donors, the U12 branch point and U12/U2 acceptors); A vector with 5 elements can be assigned which each shows the match score to use for each PWM in pwmU12U2.
refGenome	The reference genome; Object of class BSgenome. Use available.genome() from the BSgenome package to see the available genomes. DNAStringSet objects (from Biostrings package) and fasta files are also accepted as input.
setNaAs	Defines that if reference (e.g. intron) did not match any of U12 or U2 type introns based on the scores obtained from PWM what should the function return. If an intron was not proven to be U12 or U2 based on PWM scores it can be considered as U2-type since the U12 type introns constitute for about 1% of introns in human genome and they are muxh more conserved than the U2 type introns, hence the default is 'U2'; otherwise it is also possible to set it as NA or nan or 'U12/U2'.
annotateU12Subtype	Whether annotate the subtypes of the U12 type Introns. The value is TRUE by default.
includeMatchScores	If set as TRUE the final data frame result includes the PWM match scores (FALSE by default).
ignoreHybrid	Whether ignore the U12 hybrid subtypes, i.e. GT-AC and AT-AG (TRUE by default).
filterReference	Optional parameter that can be defined either as a GRanges or SummarizedExperiment object. If defined as the latter, the first 3 columns of the rowData must be: chr name, start and end of the coordinates. If the parameter is defined the introns/exon coordinates will be mapped against it and the intron type of all those that do not match will be set as NA.

Value

Data frame containing 3 columns representing (in order): intron type (U12, U2 or none), strand match indicating whether the PWM matches to the sequence (+ strand) or the reverese complement of the sequence (- strand) or none (NA), and the U12 subtype (GT-AG or AT-AC). If includeMatchScores is set as TRUE further columns that include the PWM match scores will also be included.

Author(s)

Ali Oghabian

See Also

buildSsTypePwms.

Examples

# Improting genome
BSgenome.Hsapiens.UCSC.hg19 <- 
	BSgenome.Hsapiens.UCSC.hg19::BSgenome.Hsapiens.UCSC.hg19
#Choosing subset of rows
ind<- 69:94
# Annotate U12 introns with strong U12 donor site, branch point 
# and acceptor site from the u12 data in the package
annoU12<- 
	annotateU12(pwmU12U2=list(pwmU12db[[1]][,11:17],pwmU12db[[2]]
		,pwmU12db[[3]][,38:40],pwmU12db[[4]][,11:17],
		pwmU12db[[5]][,38:40]), 
	pwmSsIndex=list(indexDonU12=1, indexBpU12=1, indexAccU12=3, 
		indexDonU2=1, indexAccU2=3), 
	referenceChr=u12[ind,'chr'], 
	referenceBegin=u12[ind,'begin'], 
	referenceEnd=u12[ind,'end'], 
	referenceIntronExon=u12[ind,"int_ex"], 
	intronExon="intron",  
	matchWindowRelativeUpstreamPos=c(NA,-29,NA,NA,NA),
	matchWindowRelativeDownstreamPos=c(NA,-9,NA,NA,NA), 
	minMatchScore=c(rep(paste(80,"%",sep=""),2), "60%", 
		paste(80,"%",sep=""), "60%"), 
	refGenome=BSgenome.Hsapiens.UCSC.hg19, 
	setNaAs="U2", 
	annotateU12Subtype=TRUE)

# How many U12 and U2 type introns with strong U12 donor sites, 
# acceptor sites (and branch points for U12-type) are there?
table(annoU12[,1])

gacatag/IntEREst documentation built on July 29, 2024, 1:12 a.m.