GLAM2Scan - MEME Suite

# The MEME Suite

## Motif-based sequence analysis tools

# GLAM2Scan

## Scanning with Gapped Motifs

### Usage:

`glam2scan [options] <alphabet> <glam2 motif file> <sequence file>`

### Description

### Input

#### <alphabet>

The alphabet of the motif and sequences. This can be 'p' for protein sequences, 'n' for nucleotide sequences or the name of an GLAM2 alphabet file.

#### <glam2 motif file>

The name of a file containing a GLAM2 motif. If the file contains multiple motifs then GLAM2SCAN only considers the top one. The file may be either GLAM2's plain text (`glam2.txt`) or HTML (`glam2.html`) output.

The minimal component of the GLAM2 motif is shown in this GLAM2 DNA motif and GLAM2 protein motif.

#### <sequence file>

The name of a file containing FASTA formatted sequences.

### Output

GLAM2Scan writes its output to files in a directory named `glam2scan_out`, which it creates if necessary. You can change the output directory using the -o or -O options. The directory will contain:

- `glam2scan.html` - an HTML file containing the results in a human-readable format
- `glam2scan.txt` - a plain text file containing the results (the HTML format contains slightly less information but is easier to read)

Output begins with some general information stating the program name, version and the actual command line:

      GLAM2scan
      Version 9999

      glam2scan p prot_motif.glam2 lotsa_prots.fa

This is followed by motif matches, sorted in order of score. A motif match looks like this:

NAME | START | SITE | END | STRAND | SCORE
--- | --- | --- | --- | --- | ---
|  | ****.*********..*********.*** |  |
At1g01140.2_SnRK3.12 | 196 | YDGAAADVWSCGVI.FVLMAGYLPFDEPN | 223 | + | 66.9

The name of the sequence with the match appears on the left; the start and end coordinates of the match appear on either side of the matching sequence; the match score appears on the right. The plus sign indicates the strand of the match (only meaningful when considering both strands of nucleotide sequences with the -2 option). The stars indicate the key positions of the motif: the alignment of the match to the key positions is shown. (The HTML format output does not include the stars over the matched sequence.)

### Options

Option | Parameter | Description | Default Behavior
--- | --- | --- | ---
Basic Options
-t |  | Output in text format only to standard output. | The program behaves as if `-O glam2scan_out` had been specified.
-n | n | Report n matches. If scores are tied, they are sorted in alphabetical order of sequence name. If sequence names are also identical, the order is arbitrary. |
-2 |  | Search both strands of nucleotide sequences. |
Advanced Options
The remaining options are somewhat specialized. For typical usage, it is reasonable to set them to exactly the same values as were used with glam2 to discover the motif.
-D | pseudocount | Specify the deletion pseudocount. |
-E | pseudocount | Specify the 'no-deletion' pseudocount. |
-I | pseudocount | Specify the insertion pseudocount. |
-J | pseudocount | Specify the 'no-insertion' pseudocount. |
-d | file | Specify a Dirichlet mixture file. |

## Motif format

Some users may wish to make 'fake' glam2 motifs for input to glam2scan, for instance based on motifs found by other tools. Most of the glam2 output is ignored by glam2scan, and a minimal motif file looks like this:

                      **..****
      seq1         10 HP..D.IG
      seq2          5 HPGADLIG
      seq3          7 HP..ELIG
      seq4          5 HP..ELLA

The sequence names and coordinates are ignored, but some placeholder characters should be present. The stars indicating key positions are necessary, and the first and last columns must be starred.

### Citing

If you use GLAM2SCAN, please cite:
MC Frith, NFW Saunders, B Kobe, TL Bailey, "Discovering sequence motifs with arbitrary insertions and deletions", PLoS Computational Biology, 4(5), e1000071, 2008. [full text]