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VIPER - Visualization Pipeline for RNA-seq

Introduction to VIPER:

VIPER is a comprehensive RNA-seq analysis tool built using snakemake which allows for ease of use, optimal speed, and a highly modular code that can be further added onto and customized by experienced users. VIPER combines the use of several dozen RNA-seq tools, suites, and packages to create a complete pipeline that takes RNA-seq analysis from raw sequencing data all the way through alignment, quality control, unsupervised analyses, differential expression, and downstream pathway analysis. In addition, VIPER has been outfitted with several recently published tools that allow for interrogation of immune and virus infiltrate. The results are compiled in a simple and highly visual report containing the key figures to explain the analysis, and then compiles all of the relevant files, tables, and pictures into an easy to navigate folder.

Table of Contents

  1. System Requirements
  2. Anatomy of a VIPER PROJECT
  3. Getting Started - One time Installation of components necessary for an individual user
  4. Setting up a Project Folder for a VIPER Run
    1. The Config File
    2. The Metasheet
  5. Running VIPER
  6. Appendix A: Dana-Farber Members
  7. Appendix B: Specific VIPER Commands for Replotting
  8. Setting up VIPER for a group of users or server

System requirements:

Some of the tools that VIPER uses, e.g. STAR and cufflinks are very memory intensive programs. Therefore we recommend the following system requirements for VIPER:

Minimal system requirements:

We recommend that you run VIPER on a server that has at least 30GB of ram. This will allow for a single-threaded VIPER run (on human samples).

We recommend that you have at least 128GB of ram and at least a 4-core CPU if you want to run VIPER in multi-threaded mode (which will speedup the workflow significantly). Our own servers have 256GB of ram and 32 cores.

Anatomy of a VIPER PROJECT: <a name="anatomy"></a>

All work in VIPER is done in a PROJECT directory, which is simply a directory to contain a single VIPER analysis run. PROJECT directories can be named anything (and they usually start with a simple mkdir command, e.g. mkdir viper_for_thesis), but what is CRITICAL about a PROJECT directory is that you fill them with the following core components: (We first lay out the directory structure and explain each element below)

PROJECT/
viper/
data/ - optional
config.yaml
metasheet.csv

The 'viper' directory contains all of the viper code. We'll explain how to download that directory below. The 'data' directory is an optional directory that contains all of your raw data. It is optional because those paths may be fully established in the config.yaml, however it is best practice to gather your raw data within 'data' using symbolic links.

The config.yaml and metasheet.csv are configurations for your VIPER run (also explained below).

After a successful VIPER run, another 'analysis' folder is generated which contains all of the resulting output files.

Getting Started - One time installation of components necessary for an individual user: <a name="GettingStarted"></a>

If you are looking to install for a system of users, we recommend you look at appendix C below. Note that this can also be a very useful step for individual users as well!

Although included in this README are step-by-step instructions, it is assumed that the user has a basic understanding of the nix command line interface.

Installing wget and git:

To get some of the required software packages, we will use the command line tools called wget and git. wget is a popular tool for downloading things off of the internet. git is a distributed version control system which we will use to checkout the VIPER code.

These tools are already pre-installed in most systems, but if you are unsure whether or not you have wget enter wget and if the return is wget: command not found, then you will have to install wget. Do likewise for git.

Installing Miniconda3:

We will be using the Miniconda3 package management system (aka CONDA) to manage all of the software packages that VIPER is dependent on.

Use following commands to retrieve and then RUN the Minicoda3 installation script:
1. wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
2. bash Miniconda3-latest-Linux-x86_64.sh

  • Whilst running the installation script, follow the commands listed on screen, and press the enter key to scroll.
  • Make sure to answer yes when asked if you want to prepend Miniconda3 to PATH.
  • Close your terminal, open a new one and you should now have Conda working! Test by entering:
    conda update conda
    • Press y to confirm the conda updates

NOTE: you will only have to install Minicoda3 once.
NOTE: remember to close your terminal session and re-login

Installing the VIPER conda environments:

We are now ready to use CONDA to install the software packages which VIPER is dependent on.

  1. wget https://bitbucket.org/cfce/viper/get/master.tar.gz
  2. tar -xf master.tar.gz
  3. mv cfce-viper-XXXXX viper
    NOTE: the XXXXX refers to the latest changeset of viper, so it will differ
  4. cd viper/envs
  5. conda env create -f environment.yml -n viper
  6. conda env create -f python2_environment.yml -n viper_py2

NOTE: you will only have to install the VIPER conda environments once.

DOWNLOADING the VIPER static reference files:

VIPER is dependent on reference files which can be found for the supported species listed below: download link hg19 mm9

To unzip these files: tar -xzf hg19.tar.gz OR tar -xzf mm9.tar.gz

BEST PRACTICE: we recommend that you download the reference files that you need and then untarring then in a directory called "VIPER_static". So for example, suppose you make "VIPER_static" in you home directory then you would have the following directory structure:

VIPER_static/
hg19/
mm9/

NOTE: you will only have to download the static references once.

Setting up your PROJECT folder for a VIPER run: <a name="SettingUpForProject"></a>

We are now ready to setup VIPER within our PROJECT folder.
If you haven't already, start by making your PROJECT folder and changing into that directory.

mkdir PROJECT
cd PROJECT

NOTE: remember, you can name your PROJECT folder anything

Linking the VIPER static reference files (optional best practice):

If you followed the BEST PRACTICE of placing the reference files in a directory called "VIPER_static" then you should create a symbolic link to that directory and name it 'ref_files':
1. cd PROJECT
2. ln -s /path/to/VIPER_static ./ref_files
NOTE: if VIPER_static is in your home directory, then the path would be ~/VIPER_static

This is the recommended BEST PRACTICE because it will ease setting up the PARAMETERS and PATHS in config.yaml described below. If you don't choose to implement this BEST PRACTICE then you can manually define the paths to the required files in config.yaml.

DOWNLOADING the VIPER source code:

Within your PROJECT directory, issue the following commands:
1. wget https://bitbucket.org/cfce/viper/get/master.tar.gz
2. tar -xf master.tar.gz
3. mv cfce-viper-XXXXX viper
NOTE: the XXXXX refers to the latest changeset of viper, so it will differ

ADVANCED: you may clone the latest version of VIPER using git

Setting up your 'data' directory (optional):

As mentioned above, we highly recommend that you pool your raw data into a directory called 'data' (within PROJECT).

IF all of your data is already centrally stored in a directory called '/some/path/to/my/data/', then symbollically link your data to your PROJECTS folder.
cd PROJECT
ln -s /some/path/to/my/data/ ./data
The 'ln -s' command creates a symbolic link from '/some/path/to/my/data/' and names it 'data'. Symbolic Links have been shown to be adequate when testing, if not, then please try one of the other solutions.

IF your files are not centrally stored:
- make a directory within PROJECT called 'data' and copy your raw files into data

Copying over the META files:

The META files (config.yaml and metasheet.csv) allow you to configure each run. They are explained in much more detail below. For now, we simply copy them from the viper source directory:

    cd PROJECT
    cp viper/config.yaml .
    cp viper/metasheet.csv .

We will explain how to edit and configure these files shortly below

What your PROJECT directory should look like (up to now):

PROJECT/
ref_files/ - optional, but BEST_PRACTICE is highly recommended
viper/
data/ -
optional*
config.yaml
metasheet.csv

NOTE: you will have to setup your PROJECT directory for each VIPER run.

Configuring the META files: config.yaml <a name="config"></a>

The config.yaml file has three main sections. PATHS, PARAMS, SAMPLES:

PATHS:

In this section, you will need to specify the location of the following static reference files.

BEST PRACTICE: IF you followed the best practices of downloading the VIPER static reference files to a directory in your home directory named "VIPER_static" and then created a symbolic link to this directory (calling the link "ref_files") then you can skip most of this section As the default config.yaml ASSUMES that ref_file points contains the VIPER STATIC reference directories (i.e. anything that starts with ./ref_files can be skipped/ignored). Simply make sure that your references are appropriate for your species/assembly. The only parts you will need to be responsible for are downloading the ref_fasta file and generating the STAR index as these were too large to include in the static reference files.

NOTE: Even if you haven't followed the BEST PRACTICE:, once you've configured your paths for your first run you can usually just use it as a template for future runs by copying it. SO this is something you probably will only have to do once!

bed_file: ./ref_files/hg19/RefGene/refseqGenesHg19.bed
- RefSeq gene file for your assembly

genome_lib_dir: ./ref_files/hg19/Hg19_CTAT_resource_lib
- path to your CTAT_resource_lib (used by STAR-Fusion module)

gtf_file: ./ref_files/hg19/Hg19_CTAT_resource_lib/ref_annot.gtf
- Gene annotation file

ref_fasta: /some/path/to/humanhg19/rawgenome/hg19.fasta
- Reference genome in a .fasta or .fa format - IMPORTANT Assemblies are not found within the VIPER_static reference files as they are prohibitively LARGE. You can download genome assemblies here at UCSC - IMPORTANT You must also index the fasta file by issuing this command
- samtools faidx [fasta file], e.g. samtools faidx hg19.fasta

reference: hg19
- What assembly (shortname) you are using, current options are hg19 and mm9

star_index: /some/path/to/STAR/humanhg19/
- star-index for the STAR aligner
- IMPORTANT STAR indices are not found within the VIPER_static reference files as they are prohibitively LARGE.
- You can generate one by running the following:
- STAR --runMode genomeGenerate --runThreadN 24 --genomeDir /where/you/want/to_store/the/output -genomeFastaFiles /dir/to/hg19/hg19.fa
- runThreadN 24 means to use 24 cores (optional parameter)

star_rRNA_index: ./ref_files/hg19/humanhg38_ncrna/
- Follow same instructions as for normal star-index

gene_annotation: viper/static/humanhg19.annot.csv
- Path to annotation files (e.g. ENSEMBL_ID, Gene Description, Go Terms, etc.). This file can be generated by using [SCRIPT that Len needs to include]. Pre-made annotations for hg19 and mm9 can be found in viper/static (simply bunzip2 them). - Simply select the appropriate .annot.csv in viper/static appropriate for your species

PARAMS:

This section holds parameters specific to your project design

metasheet: metasheet.csv
- The name and path of your metasheet. This should be within the PROJECT directory as described above. If you decide to change the name of your metasheet so it is specific to your project, you will have to change it here. for example, it is good practive to name it something like mutation_metasheet.csv

stranded: true
- MISSING

library_type: 'fr-firststrand'
- MISSING

RPKM_threshold: 1.0
- Minimum RPKM Value for a gene to be significant

min_num_samples_expressing_at_threshold: 4
- Number of samples that need to have the minimum RPKM threshold for the gene to be significant

filter_mirna: true
- Filter out MicroRNA (RNA that start with "SNO" or "MIR")

numgenes_plots: 1000
- Number of Genes to be shown in the plots of VIPER, including PCA, Sample-Sample, and Sample-Feature

num_kmeans_clust: 0,4
- Parameter for the Sample-Feature Clustering Heatmap. VIPER will interpret this list of numbers as the types of SF heatmaps the user wants. 0 means hierarchical, 4 means kmean of 4, 0,4 means both a hierarchical and a 4 kmeans clustered heatmap

snp_scan_genome: false
- Boolean Flag {true | false} on whether to perform a genome-wide snp scan IN ADDITION to the snp scan done on chr6.

cancer_type: "sarc"
- Tells VIPER to perform a TIMER analysis which will generate an estimate of immune cell type abundances in your cancer samples.
- NOTE: Your samples must be one of the following TCGA cancer types:
- Cancer types available {'kich', 'blca', 'brca', 'cesc', 'gbm', 'hnsc', 'kirp', 'lgg', 'lihc', 'luad', 'lusc', 'prad', 'sarc', 'pcpg', 'paad', 'tgct', 'ucec', 'ov', 'skcm', 'dlbc', 'kirc', 'acc', 'meso', 'thca', 'uvm', 'ucs', 'thym', 'esca', 'stad', 'read', 'coad', 'chol'}
- To ENABLE: uncomment and put in your sample's TCGA cancer type.
- To DISABLE: Comment out if not needed or set to 'False'! (default)

cdr3_analysis: false
- Boolean Flag {true | false} Tells VIPER to TRUST analysis which try to determine the CDR3 sequences in your PAIRED END samples.
- To ENABLE: uncomment and set to true
- To DISABLE: Comment out if not needed or set to false! (default)

virus_dna_scan: false
- Boolean Flag {true | false} Tells VIPER to detect viral dna sequences in your human samples.
- To ENABLE: uncomment and set to true
- To DISABLE: Comment out if not needed or set to false! (default)

SAMPLES:

In this section of the configuration file, you specify the NAMES of each sample, and the PATHS to the sample's raw data. Raw data files can either be fastq, fastq.gz, or bam formated files.

As recommended above, if all of your raw data are located in PROJECTS/data, then each path will simply start like:
'data/first.fastq'

If you did not follow the recommended best practice then you will have to specify the full paths here.

Each sample should be given a NAME (arbitrary text) and a PATH

EXAMPLE:

samples:
    SAMPLE1:
        - data/SAMPLE1.fastq.gz
    SAMPLE2:
        - data/SAMPLE2.fastq.gz
For Paired-end samples, simply add the second samples of the pait

EXAMPLE:

samples:
    SAMPLE1:
        - data/SAMPLE1_R1.fastq.gz
        - data/SAMPLE1_R2.fastq.gz
    SAMPLE2:
        - data/SAMPLE2_R1.fastq.gz
        - data/SAMPLE2_R2.fastq.gz

IMPORTANT: You cannot mix Paired-end and Single-end samples within the same VIPER run as this will cause an ERROR. If necessary, run all of one type of data first, followed by the net type of data after.

Configuring the META files: metasheet.csv <a name="metasheet"></a>

Make the metasheet file in excel, and save it as a .txt or .csv, It doesn’t matter what it is named as long as it is called in the config in the spot marked “metasheet,” see the config section if confused. The format should be something like the following:

Sample Cell Condition Treatment Replicates comp_MCF7_AvB comp_T47D_CvD
A1 MCF7 Full_Media NoDOX 1 1
A2 MCF7 Full_Media NoDOX 2 1
B1 MCF7 Full_Media DOX 1 2
B2 MCF7 Full_Media DOX 2 2
C1 T47D Full_Media NoDOX 1 1
C2 T47D Full_Media NoDOX 2 1
D1 T47D Full_Media DOX 1 2
D2 T47D Full_Media DOX 2 2
  • The first column should always be sample names that exactly match the sample names used in config.yaml (see SAMPLES just above)
  • The samples that you want to perform a Differential Expression (DE) on using limma and deseq should be marked by the “comp” columns more on this below
    • This is important! The “control” should be marked with a 1, and the “treatment” should be marked with a 2.
  • It is recommended that if you should have a “replicates” column to denote different samples, it is a good idea to not only have each of the sample names be unique, but also make sure that the associated metadata is unique as well to each sample.
  • The rest of the metadata columns are up to the user to write. Sample must always be first, and you are allowed to have as many “comp_XXXX” columns as you want at the end. All of the middle columns are your metadata (for this example, this is cell, condition, treatment, replicates)

  • Again, make this in excel so that all of the spacing is done correctly and save it out as a .txt or .csv file. This is the most common bug, so please follow this.

  • Common Problems with metasheet
  • Characters to avoid: ("-", "(", ")", " ", "/", "$") To avoid bugs, the only punctuation that should be used is the underscore “_”. Dashes, periods, etc, could cause a bug because there is a lot of table formatting and manipulation, or they are invalid characters in R. NOTE: viper parses the meta file and will convert MOST of these invalid characters into '.'--dollarsigns will just be dropped. The viper parser will also convert between dos/mac files to unix format.
    • It is very important that you know that samples A is what you mark with 1, and samples B is what you mark with a 2. You should name your output following this format as well "comp_cond_AvB” This will let the reader know what the output DE files refer to.
      • Deseq: ”baseMeanA” refers to samples A, which follows condition 1 and “baseMeanB” refers to samples B which follows condition 2. logfc is B/A
      • Limma: Logfc refers to B/A

Running VIPER: <a name="RunningViper"></a>

Now that we have setup our PROJECT directory (downloading the 'viper' code directory, creating our 'data' directory, and configuring our config.yaml and metasheet.csv), we are (finally!) ready to run VIPER.

To start, we must activate the VIPER CONDA ENVIRONMENT: source activate viper
*if successful, you will see "(viper)" prepended to your command prompt.
NOTE: you will have to do this for every VIPER run/session. Once you log-out of your terminal session, you will also log out of your VIPER CONDA ENVIRONMENT.

Next we will perform a DRY-RUN to make sure that we setup the VIPER PROJECT directory correctly. In your PROJECT folder run the following command:

snakemake --snakefile viper/viper.snakefile -n

This will return a large output which basically outlines what VIPER is about to do. If no errors come back, then you will mostly see GREEN and YELLOW print outs. If there are errors, then you will see some RED print outs.

If there are no errors, then use the following command to run VIPER:

snakemake --snakefile viper/viper.snakefile

If there are errors, try to see what the error is about. Was it a mistyped path? Etc. If all else fails, email the VIPER team (email address needed)

APPENDIX A: Dana-Farber CFCE Members: <a name="DFmembers"></a>

If you are a member of Dana-Farber and have access to the CFCE server, you will already have many of the packages you need installed globally. Please see the README within the CFCE folder of VIPER

APPENDIX B: Specific Replotting: <a name="replotting"></a>

After you have run VIPER in its entirety, you may want to go back and tweak your outputs. Maybe adding or subtracting metadata columns, differential expression columns, or maybe just doing a subset of your data. Below is a list of snakemake commands to run VIPER to rerun some specifics for further downstream analysis tweaking. Note that VIPER is built to automatically rerun downstream analysis if you adjust the config or the metasheet.

To learn about how snakemake works, and some of the specifics of the following commands and others, look into the snakemake documentation

The following are some useful commands for rerunning and adding to the download analysis without having to rerun the whole pipeline:

snakemake -s viper/viper.snakefile -n

snakemake -s viper/viper.snakefile -j 24

snakemake -s viper/viper.snakefile analysis/plots/heatmapSF_plot.pdf -f

snakemake -s viper/viper.snakefile analysis/plots/heatmapSS_plot.pdf -f

snakemake -s viper/viper.snakefile analysis/plots/pca_plot.pdf -f

Adding comp columns will automatically make it generate new differential expressions analysis and adjust figures accordingly.
"Touching" the metasheet will have VIPER rerun all downstream output.

touch metasheet.csv

APPENDIX C: Deploying for a group of users: <a name="serverSetup"></a>

NOTE: this section is by no means "the solution". It is just the particular solution that we deployed for our center.

Problem1: The install instructions above applied to single users. But suppose you work within a lab and you want all of your lab users to use VIPER. You want a way to centralize your VIPER deployment so that everyone in your lab is using the same (updated) version of VIPER.

Problem2: Installing miniconda for in your own local environment has a tendency to "clobber" the global enviroment on your system. For example, your lab/server uses python2.7, but once your install the latest miniconda pkgs, you find yourself forced to use python3.5. Or on the server, STAR ver X.Y is installed, but with conda, you are using STAR ver Z.A.

There are ways to hack around this by modifying your .bashrc but you don't even know what a .bashrc is.

Solution: One solution to these problems is to install VIPER (as above) for one "central" user--we created a 'viper' user account on our ubuntu system. And then we created a simple initialization script, 'viperSetup.sh', which setup the PROJECT directory for our users.

Let's walk through this setup in more detail:

setting up a central viper user:

  1. on your machine, create a new user--e.g. 'viper'
  2. check out the latest VIPER code: e.g. /home/viper$ git clone git@bitbucket.org:cfce/viper.git
  3. install miniconda and create the VIPER conda enviromentS, etc: see "Installing VIPER and setting up your environment" above
  4. optional but recommended: create template config.yaml and metasheet.csv that will help your users run VIPER. For example, in this template config.yaml, preset all of the paths that VIPER will need or comment out/in the options that will be commonly used in your lab.
  5. This is the key step: write a viper_env.bash script that looks like this:
export CONDA_ROOT=/home/viper/local/miniconda3  
export CONDA_ENVS_PATH=/home/viper/local/miniconda3/envs  
export PATH=$CONDA_ENVS_PATH/viper/bin:$PATH  
unset PYTHONPATH  
  • CONDA_ROOT is where you installed miniconda for user 'viper'
  • CONDA_ENVS_PATH should simply be $CONDA_ROOT/envs
  • PATH is overriding the user's PATH variable
  • and the last command is to UNSET the user's PYTHONPATH, just in case they set it b/c we want them to use 'viper's CONDA PYTHONPATH. 6. So viper's home directory might look like this:

    config.yaml
    metasheet.csv
    viper/
    viper_env.bash

  1. The final step is to write a simple bash script: viperSetup.sh to copy /home/viper/* to the local directory, i.e.: #!/bin/bash cp -r /home/viper/* .
  2. Finally, as sudo, place viperSetup.sh into a place like /usr/local/bin

Setting up and Running VIPER with the initialization procedure

So once you have setup a central viper user, the other users in the lab can start using viper by doing the following:

  1. $ mkdir PROJECT #some arbitrary PROJECT name
  2. $ cd PROJECT
  3. PROJECT$ viperSetup.sh #which will copy the central viper to the local dir
  4. PROJECT$ source viper_env.bash #which will take on the central viper's PATH
  5. PROJECT$ source activate viper #which will activate the viper conda env
    #This is where the user will have to define config.yaml and metasheet.csv
  6. (viper) PROJECT$ snakemake -s viper/viper.snakefile -n #to invoke a DRY-RUN
  7. (viper) PROJECT$ snakemake -s viper/viper.snakefile #to invoke VIPER