Error: unable to find an inherited method for function searchSeq for signature matrix
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@chrisclarkson100-11114
Last seen 2.4 years ago

I am trying to re-implement a script that I found on github (https://github.com/liz-is/ctcf-motif-imr90/blob/master/imr90_ctcf_motif_direction.R). This script finds the directionality of all CTCF sites in IMR90 cells.

I would like to use this analysis for mm9 ESC cells. However I have run into a number of problems due to the sparsity of the databases queried and I am trying to find ways around this. There is no PFM/PWM for CTCF in the mm9 genome on the database being queried and hence I am trying to find a source where I can manually import these data to run the script.

library("AnnotationHub")
library("BSgenome.Mmusculus.UCSC.mm9")
library("JASPAR2016")
library("TFBSTools")

opts <- list(name="CTCF", species = "10090") #species = mouse
pfm <- getMatrixSet(JASPAR2016, opts)[[1]]
pwm <- TFBSTools:::toPWM(pfm)

Unfrotunately the 'getMatrixSet' command didn't return results.

So instead I downloaded the pwm directly from: http://hocomoco11.autosome.ru/search?arity=mono&query=CTCF&species=mouse. (This proved extremely difficult to find.... you would think the pfm/pwm for such a common TF in such a common cell-line would be readily available).

m=read.table('CTCFL_MOUSE.H11MO.0.A.pwm', sep='\t', skip=1)
colnames(m=c('A','G','C','T'))

pwm=t(m)

> pwm
        [,1]      [,2]      [,3]       [,4]       [,5]        [,6]      [,7]      [,8]       [,9]
A -0.2503432 -1.479023 -2.574059  0.3141615 -0.9277147 -1.51467606  1.273071 -3.563451 -0.3816056
G -0.2101574  1.176990  1.344214 -0.8315814  0.7048456  0.85812193 -2.153051 -3.563451 -4.3917302
C  0.6396630 -1.056784 -3.116717  0.4603267  0.4244349 -1.10379501 -1.551647  1.368878  1.1867805
T -0.6632622 -1.714934 -3.116717 -0.4927609 -2.9510810  0.08597924 -2.300909 -4.391730 -3.5634514
       [,10]     [,11]     [,12]     [,13]      [,14]      [,15]      [,16]       [,17]       [,18]
A -1.6715458 -3.116717 -3.894180 -1.629962 -0.6031399 -2.3009085 -0.7955746 -0.06384649 -1.05678409
G -1.5146761 -3.563451 -2.474486  1.323185 -3.8941799  1.1393962  0.4399751  0.22266277  0.37631039
C  1.1393962  1.360724  1.316789 -4.391730  1.2250123 -0.5059102 -0.9481023  0.46032674  0.04104507
T -0.7608194 -3.563451 -1.807804 -3.315342 -3.5634514 -1.7602913  0.4753232 -1.47902311  0.14291340

ctcf_imr90_seqs <- getSeq(Mmusculus, ctcf_imr90)
imr90_matches <- lapply(ctcf_imr90_seqs, function(s){
  searchSeq(pwm, s, min.score = "75%")}) #### ERROR

Error in (function (classes, fdef, mtable)  :
  unable to find an inherited method for function ‘searchSeq’ for signature ‘"matrix"’

So it seems that the TFBSTools- searchSeq() command requires a particular class of input. When investigating the class of a normal pwm downloaded from JASPAR via 'JASPAR2014':

> opts <- list(name="CTCF", species = "9606") #species = human
> pfm <- getMatrixSet(JASPAR2016, opts)[[1]]
> pwm <- TFBSTools:::toPWM(pfm)
> class(pwm)
[1] "PWMatrix"
attr(,"package")
[1] "TFBSTools"

So my question is how can I go about importing my manually downloaded pwm into R such that the 'TFBSTools:::searchSeq()' function will accept it and run the intended analysis?

pwm tfbstools jaspar • 1.2k views
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Ge Tan ▴ 20
@ge-tan-7918
Last seen 3.7 years ago
Switzerland

You can manually create the PWMatrix class.

PWMatrix(ID="Unknown", name="CTCF", matrixClass="Unknown",
         strand="+", bg=c(A=0.25, C=0.25, G=0.25, T=0.25),
         tags=list(), profileMatrix=pwm, pseudocounts=numeric())
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