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by Jan Grau, Stefan Posch, Ivo Grosse, and Jens Keilwagen

ChIPper is a universal tool for de-novo motif discovery. ChIPper has successfully been applied to ChIP-seq, ChIP-exo and protein-binding microarray (PBM) data.

We provide ChIPper as a public web-server, a web-application that can be installed in a local Galaxy server, and as a command line program.

ChIPper web-server

ChIPper is available as a public web-server at galaxy.informatik.uni-halle.de.

Download

ChIPper is implemented in Java using Jstacs. You can download the command line application as a Jar. In addition, we provide the Jar of the Galaxy web-application for installing it in your local Galaxy server.

ChIPper will be part of the next public release of the Jstacs library.

Running the command line application

For running the command line application, Java v1.6 or later is required.

The arguments of the command line application have the following meaning:

name comment type

home Home directory (The path to the directory containing the input file. Output files are written to this directory as well., default = ./) String
data Input file (The file name of the file containing the input sequences in annotated FastA format (see readme)) String
infix Infix (a infix to be used for all output files (model, sequence logos, predicted binding sites)) String
motifLength Position tag (The tag for the position information in the FastA-annotation of the input file) String
starts Value tag (The tag for the value information in the FastA-annotation of the input file) String
motifOrder Weighting factor (The value for weighting the data; either a value between 0 and 1, or a description relative to the standard deviation (e.g. +4sd), default = 0.2) Double
bgOrder Starts (The number of pre-optimization runs., valid range = [1, 100], default = 20) Integer
position Initial motif width (The motif width that is used initially, may be adjusted during optimization., valid range = [1, 50], default = 15) Integer
value Markov order of motif model (The Markov order of the model for the motif., valid range = [0, 3], default = 0) Integer
weightingFactor Markov order of background model (The Markov order of the model for the background sequence and the background sequence, -1 defines uniform distribution., valid range = [-1, 5], default = -1) Integer
ess Equivalent sample size (Reflects the strength of the prior on the model parameters., valid range = [0.0, Infinity], default = 4.0) Double
delete Delete BSs from profile (A switch for deleting binding site positions of discovered motifs from the profile before searching for futher motifs., default = true) Boolean
threads Compute threads (The number of threads that are use to evaluate the objective function and its gradient., valid range = [1, 128], OPTIONAL) Integer


Installing the web-application

The command-line program behind the web-application is a Jar as well, so Java is required on the server running Galaxy. To install this command line program in Galaxy, copy it to the desired destination in the Galaxy tools directory.

The command line application writes its Galaxy tool definition file itself. If you are in the directory containing the command-line program for Galaxy, you can create the tool definition file by calling

java -jar ChIPperWeb.jar --create ChIPperWeb.xml

Afterwards, this directory contains the tool definition file ChIPperWeb.xml. Now you can register ChIPper in the Galaxy tool_conf.xml file. For details, see the Galaxy tutorial for adding new tools.