SPADE is a software to explore various periodic repeat regions comprehensively from large genomic and protein data resources. The software first automatically extracts multiple sequence entries from an input file (GenBank or FASTA format) and identifies sequence type (DNA or protein) for each entry. Each sequence entry is scanned by a sliding window to count k-mers and highly repetitive regions are extracted. The sequence periodicity of each highly repetitive region is then evaluated based on position-period matrix that cumulatively plots distance between neighboring same k-mers and their sequence positions. The periodic sequence region is defined and the periodic sequence units are queried for a multiple alignment to identify repetitive motif and its sequence logo. The representative motif sequence is aligned back to the sequence of the periodically repeating region to annotate the repeating units. Finally, the annotations for detected periodic repeats are added to the input information and output in GenBank format with an option of visualizing k-mer density, position-periodicity matrix, sequence motif logo and repetitive unit loci with neighboring genes for each periodic repeat (Fig. 1a).
Figure 1. Example visualizations of periodic repeat regions captured by SPADE. (a) A CRISPR-surrounding region of Streptococcus thermophilus LMD-9. (b) A circular genome map visualization of S. thermophilus LMD-9 genome with all of the periodic biomolecular sequences detected by SPADE.
SPADE works under Python 2.7.13 or Python 3.6.1 and require BLAST (ver 2.6.0 later) and MAFFT (ver 7.221 later) to be installed.
1. Obtain SPADE github packages using the following single command.
git clone https://github.com/yachielab/SPADE
To execute SPADE using linux/unix commands, add the SPADE directory to $PATH and add executable authority to the python scripts in the directory.
cd SPADE
chmod u x *.py
2. Install the necessary Python packages using the following commands.
pip install matplotlib==2.2.3
pip install seaborn==0.8.1
pip install weblogo==3.6.0
pip install biopython
If pip is not installed, please download get-pip.py](https://bootstrap.pypa.io/get-pip.py) and install pip using the following command.
python get-pip.py
*If you use default Python in OSX or macOS and encounter the following message when get-pip.py is executed,
matplotlib 1.3.1 requires nose, which is not installed.
matplotlib 1.3.1 requires tornado, which is not installed.
please use the following commands,
pyhton get-pip.py --user
pip install --user -I seaborn
pip install --user -I weblogo
pip install --user -I biopython
and set PYTHONPATH to /Users/[USER_NAME]/Library/Python/2.7/lib/python/site-packages
3. Install MAFFT if it is not installed. MAFFT package is available at the following links.
Set $PATH to the MAFFT executable.
4. Install BLAST if it is not installed. Executable BLAST package is available at the following links.
Set $PATH to the BLAST executable.
The package contains a GenBank file for the Streptococcus thermophilus LMD-9 genome so users can quickly test the functions of SPADE with the following operations.
1. Go to the example folder and execute SPADE to screen periodic repeats in the sequence entries included in the GenBank file.
SPADE.py -in GCF_000014485.1_ASM1448v1_genomic.gbff
As this GenBank file contains three sequence entries, SPADE creates three folders NC_008532.1 for the genomic DNA, NC_008500.1 and NC_008501.1 for two plasmid DNAs. See below for the detail of output data format.
2. If you want to additionally create a circular genome map with cumulative k-mer scores and detected periodic repeats as represented in Fig. 1b, go to the folder NC_008532.1 and simply type the following command.
genome_circular_plot.py NC_008532.1_SPADE.gb NC_008532.1_kmer_count.txt
3. If you want to additionally create a table representing all of the periodic repeats detected by SPADE, type the following command.
get_spade_annotation.py NC_008532.1_SPADE.gb
Structures of output directories
If your input a sequence file contains multiple sequence entries, SPADE creates multiple folders for different entries under your current directory. For GenBank files, each LOCUS entry is treated as one sequence entry and each folder can contain results for multiple DNA and protein sequences. In each [entry] folder, SPADE creates [entry].gbk that involves annotations for the detected periodic repeats in addition to the information in the original query file. In the same folder, a descendant folder is created to store all the results for each detected periodic repeat. The directory structure therefore looks as follows.
(current directory)/
----[entry].gbk
----[entry]/
----[type]_[start]_[end]/
where [type] is nucl or prot indicating that if the repeat sequence type is nucleotide or protein, respectively, and [start] and [end] denote position of the repeat region in entry sequence.
Output files in each descendant folder
For each detected repeat, the following files will be created.
- repeat.gbk contains locus information for the detected repeat and its surrounding genes
- k-mer.tsv contains a cumulative k-mer count distribution across the detected repeat region
- ppm.tsv contains a position-period matrix for the detected repeat region
- ppm4vis.tsv contains a position-period matrix trimmed for visualization
- pdist.tsv contains a distribution of detected periods
- unit_seq.fasta contains multiple sequences that are used to find a repeat motif
- align.unit_seq.fasta contains a multiple alignment result of the detected repeat motif
- periodic_repeat.pdf visualizes the contents in repeat.gbk, k-mer.tsv,
- ppm4vis.tsv and pdist.tsv as represented in Fig. 1a
- weblogo.pdf represents sequence logo for the detected motif
- weblogo.txt is a raw data used produce weblogo.pdf
SYNOPSIS
SPADE [-h] [--help] [-in input_file] [-f input_file_format] [-t sequence_type]
[-Nk kmer_size] [-Nw window_size] [-Ns kmer_score_threshold] [-Ng gap_size]
[-Nm region_margin] [-Np period_threshold] [-Nq gap_frequency_threshold]
[-Nu motif_letter_consistency] [-Nr non_consensus_length_threshold]
[-Pk kmer_size] [-Pw window_size] [-Ps kmer_score_threshold] [-Pg gap_size]
[-Pm region_margin] [-Pp period_threshold] [-Pq gap_frequency_threshold]
[-Pu motif_letter_consistency] [-Pr non_consensus_length_threshold]
[--mafft string] [--blast string] [-n num_threads] [-v string] [-d] [--delete]
[-V] [--version]
DESCRIPTION
SPADE 1.0.0
OPTIONAL ARGUMENTS
-h, --help
Print USAGE, DESCRIPTION and ARGUMENTS; ignore all other parameters
-V, --version
Print software version; ignore all other parameters
*** Input query options
-in <File_In>
Input file name
-f <String, Permissible values: ‘genbank’ ‘fasta’ ‘auto’>
Input file type
Default = ‘auto’
-t <String, Permissible values: ‘nucl’ ‘prot’ ‘auto’>
Sequence type, nucleotide (nucl) or protein (prot)
Default = ‘auto’
*** General screening options for nucleotide periodic repeats
-Nk <Integer>
k-mer size
Default = 10
-Nw <Integer>
Size of sliding window to calculate cumulative k-mer distribution
Default = 1000
-Ns <Integer>
Threshold for peak height of each cumulative k-mer count area
Default = 20
-Ng <Integer>
Threshold for gap size between significant k-mer count areas
Default = 200
-Nm <Integer>
Size of margin to be evaluated with each detected highly repetitive region
Default = 1000
-Np <Real>
Periodicity score threshold for each detected highly repetitive region
Default = 0.5
-Nq <Real>
Gap frequency threshold for each position of a repeat motif to be removed
Default = 0.5
-Nu <Real>
Threshold for letter consistency score at each position of a repeat motif
Default = 0.8
-Nr <Integer>
Threshold for length of non-consensus region to be removed from a repeat motif
Default = 5
*** General screening options for protein periodic repeats
-Pk <Integer>
k-mer size
Default = 3
-Pw <Integer>
Size of sliding window to calculate cumulative k-mer distribution
Default = 300
-Ps <Integer>
Threshold for peak height of each cumulative k-mer count area
Default = 6
-Pg <Integer>
Threshold for gap size between significant k-mer count areas
Default = 50
-Pm <Integer>
Size of margin to be evaluated with each detected highly repetitive region
Default = 300
-Pp <Real>
Periodicity score threshold for each detected highly repetitive region
Default = 0.3
-Pq <Real>
Gap frequency threshold for each position of a repeat motif to be removed
Default = 0.5
-Pu <Real>
Threshold for letter consistency score at each position of a repeat motif
Default = 0.8
-Pr <Integer>
Threshold for length of non-consensus region to be removed from a repeat motif
Default = 5
*** MAFFT and BLAST options
--mafft <'String'>
Optional arguments for MAFFT can be defined with single quotations
Default = '--auto'
For MAFFT optional arguments, see
https://mafft.cbrc.jp/alignment/software/manual/manual.html
--blastn <'String'>
Optional arguments for BLAST can be defined with single quotations
Default = '-strand plus -task blastn-short -penalty -2 –outfmt "6 qseqid qseq sseqid sseq pident qlen length mismatch gapopen qstart qend sstart send gaps evalue bitscore"'
--blastp <'String'>
Optional arguments for BLAST can be defined with single quotations
Default = '-task blastp-short –outfmt "6 qseqid qseq sseqid sseq pident qlen length mismatch gapopen qstart qend sstart send gaps evalue bitscore"'
For BLAST optional arguments, see
https://www.ncbi.nlm.nih.gov/books/NBK279684/
*** Other options
-n <Integer>
Number of CPU threads. If this is set to more than 1, SPADE runs multiple
processes for multiple sequence entries in parallel.
Default = 1
-v <String, Permissible values: 'Y' 'N'>
Generate pdf files to visualize results for each detected repeat region
Default = Y
-d, --delete
This option deletes descendant output folders of highly repetitive regions
that are detected not to contain periodic repeats