XMatrix {TFBSTools} | R Documentation

## `"XMatrix"` objects

### Description

XMatrix is a virtual class. No objects can be created from it directly. Three classes are derived from this class: PFMatrix, PWMatrix and ICMatrix.

PFMatrix is a class whose instances are objects representing raw position frequency matrices (PFMs).

PWMatrix is a class whose instances are objects representing position weight matrices (PWMs). Compared with PFMatrix, it has extra slot `pseudocounts`.

ICMatrix is a class whose instances are objects representing information content matrices (ICMs). Compared with PWMatrix, it has extra slot `schneider`.

### Usage

    ## Constructors:
    PFMatrix(ID="Unknown", name="Unknown", matrixClass="Unknown",
             strand="+", bg=c(A=0.25, C=0.25, G=0.25, T=0.25),
             tags=list(), profileMatrix=matrix())
    PWMatrix(ID="Unknown", name="Unknown", matrixClass="Unknown",
             strand="+", bg=c(A=0.25, C=0.25, G=0.25, T=0.25),
             tags=list(), profileMatrix=matrix(), pseudocounts=numeric())
    ICMatrix(ID="Unknown", name="Unknown", matrixClass="Unknown",
             strand="+", bg=c(A=0.25, C=0.25, G=0.25, T=0.25),
             tags=list(), profileMatrix=matrix(), pseudocounts=numeric(),
             schneider=logical())
    ## Accessor-like methods:
    ## S4 method for signature 'XMatrix'
    ID(x)
    ## S4 method for signature 'XMatrix'
    bg(x)

    ## ... and more (see Methods)

### Arguments

`ID` | Object of class `"character"`: A unique identifier for each matrix.
`name` | Object of class `"character"`: The name of the transcription factor. In JASPAR, as far as possible, the name is based on the standardized Entrez gene symbols. In the case the model describes a transcription factor hetero-dimer, two names are concatenated, such as RXR-VDR. In a few cases, different splice forms of the same gene have different binding specificity: in this case the splice form information is added to the name, based on the relevant literature.
`matrixClass` | Object of class `"character"`: Structural class of the transcription factor, based on the TFCaT system
`strand` | Object of class `"character"`: Which strand is the binding sites sequences from.
`bg` | Object of class `"numeric"`: Background frequencies of the four bases. By default, it is equally 0.25.
`tags` | Object of class `"list"`: Some tags information about this model. Tags include: (1) "family": Structural sub-class of the transcription factor, based on the TFCaT system. (2) "species": The species source for the sequences, in NCBI tax IDs. (3) "tax_group": Group of species, currently consisting of 4 larger groups: vertebrate, insect, plant, chordate. (4) "medline": a ID to the relevant publication reporting the sites used in the mode building. (5) "type": Methodology used for matrix construction. (6) "ACC": A representative protein accession number in Genbank for the transcription factor. Human takes precedence if several exists. (6) "pazar_tf_id": a ID to PAZAR database. (7) "TFBSshape_ID": a ID to TFBSshape database. (8) "TFencyclopedia_ID": a ID to the Transcription Factor Encyclopedia. (9) "comment": For some matrices, a curator comment is added.
`profileMatrix` | Object of class `"matrix"`: This is the matrix information.
`pseudocounts` | Object of class `"numeric"`: This is the pseudocounts used when computing ICM or PWM from PFM. By default, a threshold of 0.8 is used based on the previous research (doi:10.1093/nar/gkn1019).
`schneider` | Obejct of class `"logical"`: this logical value indicates whether the schneider correction is used during the conversion from PFM to ICM.
`x` | Object of class `XMatrix`.

### Value

A `XMatrix` object.

### Methods

bg

  `signature(x = "XMatrix")`: Gets the background base frequencies.

bg<-

  `signature(x = "XMatrix")`: Sets the background base frequencies.

ID

  `signature(x = "XMatrix")`: Gets the ID information.

ID<-

  `signature(x = "XMatrix")`: Sets the ID information.

length

  `signature(x = "XMatrix")`: Gets the pattern length in nucleotides (i.e. number of columns in the matrix).

reverseComplement

  `signature(x = "PWMatrix")`: Generates the reverse complement matrix object. Note than the strand is XMatrix will also be changed to the opossite strand.

as.matrix

  `signature(x = "XMatrix")`: Returns the matrix in the XMatrix class.

totalIC

  `signature(x = "ICMatrix")`: Returns the information content vector.

Matrix

  `signature(x = "XMatrix")`: Gets the matrix stored in `XMatrix` object.

Matrix<-

  `signature(x = "XMatrix")`: Sets the matrix stored in `XMatrix` object.

matrixClass

  `signature(x = "XMatrix")`: Gets the matrix type of a `XMatrix` object.

matrixClass<-

  `signature(x = "XMatrix")`: Sets the matrix type of a `XMatrix` object.

name

  `signature(x = "XMatrix")`: Gets the name information.

name<-

  `signature(x = "XMatrix")`: Sets the name information.

strand

  `signature(x = "XMatrix")`: Gets the strand information of a `XMatrix` object.

tags

  `signature(x = "XMatrix")`: Gets a `list` object of tags information.

### Author(s)

Ge Tan

### See Also

`toPWM`, `toICM`

### Examples

      ## Constructorpf PFMatrix
      ## Note that there is no XMatrix() constructor,
      ## but an XMatrix family of constructors: PFMatrix(), PWMatrix(), ICMatrix()
      pfm <- PFMatrix(ID="MA0004.1", name="Arnt", matrixClass="Zipper-Type",
                      strand="+", bg=c(A=0.25, C=0.25, G=0.25, T=0.25),
                      tags=list(family="Helix-Loop-Helix", species="10090",
                      tax_group="vertebrates", medline="7592839", type="SELEX",
                      ACC="P53762", pazar_tf_id="TF0000003",
                      TFBSshape_ID="11", TFencyclopedia_ID="580"),
                      profileMatrix=matrix(c(4,  19, 0,  0,  0,  0,
                                             16, 0,  20, 0,  0,  0,
                                             0,  1,  0,  20, 0,  20,
                                             0,  0,  0,  0,  20, 0),
                                             byrow=TRUE, nrow=4,
                                             dimnames=list(c("A", "C", "G", "T")))
                     )

      ## Construction from a set of binding sites sequences
      sitesSeqs <- c("Human Gli1"= "GACCACCCA", "hIGFBP-6"= "GACCCCCCA",
                     "HNF-3beta"="GAACACCCA", "hPlakoglobin"= "GACCACCAA",
                     "rIGFBP-6"= "GTCCACCCA", "Sox-9"= "GGCCACCCA")
      countMatrix <- consensusMatrix(sitesSeqs)
      pfm <- PFMatrix(ID="Gli-1", name="Gli-1", profileMatrix=countMatrix)

      ## Coersion
      as.matrix(pfm)
      as(pfm, "matrix")

      ## Methods
      pwm <- toPWM(pfm)
      reverseComplement(pwm)
      length(pfm)

[Package TFBSTools version 1.28.0 Index]