CRISPRseek (version 1.12.0)

compare2Sequences: Compare 2 input sequences/sequence sets for possible guide RNAs (gRNAs)

Description

Generate all possible guide RNAs (gRNAs) for two input sequences, or two sets of sequences and generate scores for potential off-targets in the other sequence.

Usage

compare2Sequences(inputFile1Path, inputFile2Path, inputNames=c("Seq1", "Seq2"), format = c("fasta", "fasta"), header=FALSE, findgRNAsWithREcutOnly = FALSE, searchDirection=c("both","1to2", "2to1"), BSgenomeName, REpatternFile=system.file("extdata", "NEBenzymes.fa", package = "CRISPRseek"), minREpatternSize = 6, findgRNAs = c(TRUE, TRUE), removegRNADetails = c(FALSE, FALSE), exportAllgRNAs = c("no", "all", "fasta", "genbank"), annotatePaired =  FALSE, overlap.gRNA.positions = c(17, 18), findPairedgRNAOnly = FALSE, min.gap = 0, max.gap = 20, gRNA.name.prefix = "gRNA", PAM.size = 3, gRNA.size = 20, PAM = "NGG", PAM.pattern = "N[A|G]G$", allowed.mismatch.PAM = 2, max.mismatch = 3, outputDir, upstream = 0, downstream = 0, weights = c(0, 0, 0.014, 0, 0, 0.395, 0.317, 0, 0.389, 0.079, 0.445, 0.508, 0.613, 0.851, 0.732, 0.828, 0.615, 0.804, 0.685, 0.583), overwrite = FALSE, baseBeforegRNA = 4, baseAfterPAM = 3, featureWeightMatrixFile = system.file("extdata", "DoenchNBT2014.csv", package = "CRISPRseek"), foldgRNAs = FALSE, gRNA.backbone="GUUUUAGAGCUAGAAAUAGCAAGUUAAAAUAAGGCUAGUCCGUUAUCAACUUGAAAAAGUGGCACCGAGUCGGUGCUUUUUU", temperature = 37, scoring.method = c("Hsu-Zhang", "CFDscore"), subPAM.activity = hash( AA =0, AC =  0, AG = 0.259259259, AT = 0, CA = 0, CC = 0, CG = 0.107142857, CT = 0, GA = 0.069444444, GC = 0.022222222, GG = 1, GT = 0.016129032, TA = 0, TC = 0, TG = 0.038961039, TT = 0), subPAM.position = c(22, 23), mismatch.activity.file = system.file("extdata", "NatureBiot2016SuppTable19DoenchRoot.csv", package = "CRISPRseek") )

Arguments

inputFile1Path
Sequence input file 1 path that contains one of the two sequences to be searched for potential gRNAs
inputFile2Path
Sequence input file 2 path that contains one of the two sequences to be searched for potential gRNAs
inputNames
Name of the input sequences when inputFile1Path and inputFile2Path are DNAStringSet instead of file path
format
Format of the input files, fasta, fastq and bed format are supported, default fasta
header
Indicate whether the input file contains header, default FALSE, only applies to bed format
findgRNAsWithREcutOnly
Indicate whether to find gRNAs overlap with restriction enzyme recognition pattern
searchDirection
Indicate whether perfrom gRNA in both sequences and off-target search against each other (both) or search gRNA in input1 and off-target analysis in input2 (1to2), or vice versa (2to1)
BSgenomeName
BSgenome object. Please refer to available.genomes in BSgenome package. For example, BSgenome.Hsapiens.UCSC.hg19 for hg19, BSgenome.Mmusculus.UCSC.mm10 for mm10, BSgenome.Celegans.UCSC.ce6 for ce6, BSgenome.Rnorvegicus.UCSC.rn5 for rn5, BSgenome.Drerio.UCSC.danRer7 for Zv9, and BSgenome.Dmelanogaster.UCSC.dm3 for dm3
REpatternFile
File path containing restriction enzyme cut patters
minREpatternSize
Minimum restriction enzyme recognition pattern length required for the enzyme pattern to be searched for, default 6
findgRNAs
Indicate whether to find gRNAs from the sequences in the input file or skip the step of finding gRNAs, default TRUE for both input sequences. Set it to FALSE if the input file contains user selected gRNAs plus PAM already.
removegRNADetails
Indicate whether to remove the detailed gRNA information such as efficacy file and restriction enzyme cut sites, default false for both input sequences. Set it to TRUE if the input file contains the user selected gRNAs plus PAM already.
exportAllgRNAs
Indicate whether to output all potential gRNAs to a file in fasta format, genbank format or both. Default to no.
annotatePaired
Indicate whether to output paired information, default to FALSE
overlap.gRNA.positions
The required overlap positions of gRNA and restriction enzyme cut site, default 17 and 18
findPairedgRNAOnly
Choose whether to only search for paired gRNAs in such an orientation that the first one is on minus strand called reverse gRNA and the second one is on plus strand called forward gRNA. TRUE or FALSE, default FALSE
min.gap
Minimum distance between two oppositely oriented gRNAs to be valid paired gRNAs. Default 0
max.gap
Maximum distance between two oppositely oriented gRNAs to be valid paired gRNAs. Default 20
gRNA.name.prefix
The prefix used when assign name to found gRNAs, default gRNA, short for guided RNA.
PAM.size
PAM length, default 3
gRNA.size
The size of the gRNA, default 20
PAM
PAM sequence after the gRNA, default NGG
PAM.pattern
Regular expression of PAM, default N[A|G]G$
allowed.mismatch.PAM
Number of degenerative bases in the PAM sequence, default to 2 for N[A|G]G PAM
max.mismatch
Maximum mismatch allowed to search the off targets in the other sequence, default 3
outputDir
the directory where the sequence comparison results will be written to
upstream
upstream offset from the bed input starts to search for gRNA and/or offtargets, default 0
downstream
downstream offset from the bed input ends to search for gRNA and/or offtargets, default 0
weights
numeric vector size of gRNA length, default c(0, 0, 0.014, 0, 0, 0.395, 0.317, 0, 0.389, 0.079, 0.445, 0.508, 0.613, 0.851, 0.732, 0.828, 0.615, 0.804, 0.685, 0.583) which is used in Hsu et al., 2013 cited in the reference section
overwrite
overwrite the existing files in the output directory or not, default TRUE
baseBeforegRNA
Number of bases before gRNA used for calculating gRNA efficiency, default 4
baseAfterPAM
Number of bases after PAM used for calculating gRNA efficiency, default 3
featureWeightMatrixFile
Feature weight matrix file used for calculating gRNA efficiency. By default DoenchNBT2014 weight matrix is used. To use alternative weight matrix file, please input a csv file with first column containing significant features and the second column containing the corresponding weights for the features. Please see Doench et al., 2014 for details.
foldgRNAs
Default FALSE. If set to TRUE, summary file will contain minimum free energy of the secondary structure of gRNA with gRNA backbone from GeneRfold package provided that GeneRfold package has been installed.
gRNA.backbone
gRNA backbone constant region sequence. Default to the sequence in Sp gRNA backbone.
temperature
temperature in celsius. Default to 37 celsius.
scoring.method
Indicates which method to use for offtarget cleavage rate estimation, currently two methods are supported, Hsu-Zhang and CFDscore
subPAM.activity
Applicable only when scoring.method is set to CFDscore A hash to represent the cleavage rate for each alternative sub PAM sequence relative to preferred PAM sequence
subPAM.position
Applicable only when scoring.method is set to CFDscore The start and end positions of the sub PAM. Default to 22 and 23 for SP with 20bp gRNA and NGG as preferred PAM
mismatch.activity.file
Applicable only when scoring.method is set to CFDscore A comma separated (csv) file containing the cleavage rates for all possible types of single nucleotide mismatche at each position of the gRNA. By default, using the supplemental Table 19 from Doench et al., Nature Biotechnology 2016

Value

Return a data frame with all potential gRNAs from both sequences. In addition, a tab delimited file scoresFor2InputSequences.xls is also saved in the outputDir, sorted by scoreDiff descending.
name
name of the gRNA
gRNAPlusPAM
gRNA plus PAM sequence
targetInSeq1
target/off-target sequence including PAM in the 1st input sequence file
targetInSeq2
target/off-target sequence incuding PAM in the 2nd input sequence file
guideAlignment2Offtarget
alignment of gRNA to the other input sequence (off-target sequence)
offTargetStrand
strand of the other sequence (off-target sequence) the gRNA align to
scoreForSeq1
score for the target sequence in the 1st input sequence file
scoreForSeq2
score for the target sequence in the 1st input sequence file
mismatch.distance2PAM
distances of mismatch to PAM, e.g., 14 means the mismatch is 14 bp away from PAM
n.mismatch
number of mismatches between the off-target and the gRNA
targetSeqName
the name of the input sequence where the target sequence is located
scoreDiff
scoreForSeq1 - scoreForSeq2
bracket.notation
folded gRNA in bracket notation
mfe.sgRNA
minimum free energy of sgRNA
mfe.diff
mfe.sgRNA-mfe.backbone
mfe.backbone
minimum free energy of the gRNA backbone by itself

Details

References

Patrick D Hsu, David A Scott, Joshua A Weinstein, F Ann Ran, Silvana Konermann, Vineeta Agarwala, Yinqing Li, Eli J Fine, Xuebing Wu, Ophir Shalem, Thomas J Cradick, Luciano A Marraffini, Gang Bao & Feng Zhang (2013) DNA targeting specificity of rNA-guided Cas9 nucleases. Nature Biotechnology 31:827-834

See Also

CRISPRseek

Examples

Run this code
    library(CRISPRseek)
    inputFile1Path <- system.file("extdata", "rs362331T.fa",
            package = "CRISPRseek")
    inputFile2Path <- system.file("extdata", "rs362331C.fa",
            package = "CRISPRseek")
    REpatternFile <- system.file("extdata", "NEBenzymes.fa", 
            package = "CRISPRseek")
    seqs <- compare2Sequences(inputFile1Path, inputFile2Path,
        outputDir = getwd(), 
        REpatternFile = REpatternFile, overwrite = TRUE)

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