trusty (3) Bio::Tools::RNAMotif.3pm.gz
NAME
Bio::Tools::RNAMotif - A parser for RNAMotif output
SYNOPSIS
use Bio::Tools::RNAMotif;
my $parser = Bio::Tools::RNAMotif->new(-file => $rna_output,
-motiftag => 'protein_bind'
-desctag => 'TRAP_binding');
#parse the results
while( my $motif = $parser->next_prediction) {
# do something here
}
DESCRIPTION
Parses raw RNAMotif output. RNAMotif uses a RNA profile, consisting of sequence and structural elements
stored in a descriptor file, to search for potential motifs in a DNA sequence file. For more
information, see:
Macke TJ, Ecker DJ, Gutell RR, Gautheret D, Case DA, Sampath R. RNAMotif, an RNA secondary structure
definition and search algorithm. Nucleic Acids Res. 2001 Nov 15;29(22):4724-35.
http://www.scripps.edu/mb/case/casegr-sh-3.5.html.
This module is not currently complete. As is, it will parse raw RNAMotif output (i.e. information not
passed through the secondary programs rmfmt or rm2ct) and pack information into Bio::SeqFeature::Generic
objects. Currently, parsing extra output utilized by the sprintf() function in an RNAMotif descriptor is
not implemented; this information is instead packed into the score tag, which can be accessed by using
the following:
my ($score) = $feature->score;
If the score contains anything besides a digit, it will throw a warning that sprintf() may have been
used. Several values have also been added in the 'tag' hash. These can be accessed using the following
syntax:
my ($entry) = $feature->get_Annotations('secstructure');
Added tags are :
descline - entire description line (in case the regex used for
sequence ID doesn't adequately catch the name
descfile - name of the descriptor file (may include path to file)
secstrucure - contains structural information from the descriptor
used as a query
sequence - sequence of motif, separated by spaces according to
matches to the structure in the descriptor (in
SecStructure).
See t/RNAMotif.t for example usage.
The clean_features method can also be used to return a list of seqfeatures (in a
Bio::SeqFeature::Collection object) that are within a particular region. RNAMotif is prone with some
descriptors to returning redundant hits; an attempt to rectify this problem is attempted with RNAMotif's
companion program rmprune, which returns the structure with the longest helices (and theoretically the
best scoring structure). However, this doesn't take into account alternative foldings which may score
better. This method adds a bit more flexibility, giving the user the ability to screen folds based on
where the feature is found and the score. Passing a positive integer x screens SeqFeatures based on the
highest score within x bp, while a negative integer screens based on the lowest score. So, to return the
highest scoring values within 20 bp (likely using an arbitrary scroing system in the SCORE section of a
descriptor file), one could use:
$list = $obj->clean_features(20);
... and returning the lowest scoring structures within the same region (when the score is based on
calculated free energies from efn2) can be accomplished by the following:
$list = $obj->clean_features(-20);
If you wanted the best feature in a sequence, you could set this to a large number, preferrably on that
exceeds the bases in a sequence
$list = $obj->clean_features(10000000);
Each seqfeature in the collection can then be acted upon:
@sf = $list->get_all_features;
for my $f (@sf) {
# do crazy things here
}
At some point a more complicated feature object may be used to support this data rather than forcing most
of the information into tag/value pairs in a SeqFeature::Generic. This will hopefully allow for more
flexible analysis of data (specifically RNA secondary structural data). It works for now...
FEEDBACK
Mailing Lists
User feedback is an integral part of the evolution of this and other Bioperl modules. Send your comments
and suggestions preferably to the Bioperl mailing list. Your participation is much appreciated.
bioperl-l@bioperl.org - General discussion
http://bioperl.org/wiki/Mailing_lists - About the mailing lists
Support
Please direct usage questions or support issues to the mailing list:
bioperl-l@bioperl.org
rather than to the module maintainer directly. Many experienced and reponsive experts will be able look
at the problem and quickly address it. Please include a thorough description of the problem with code and
data examples if at all possible.
Reporting Bugs
Report bugs to the Bioperl bug tracking system to help us keep track of the bugs and their resolution.
Bug reports can be submitted via the web:
https://redmine.open-bio.org/projects/bioperl/
AUTHOR - Chris Fields
Email cjfields-at-uiuc-dot-edu
APPENDIX
The rest of the documentation details each of the object methods. Internal methods are usually preceded
with a _
new
Title : new
Usage : my $obj = Bio::Tools::RNAMotif->new();
Function: Builds a new Bio::Tools::RNAMotif object
Returns : an instance of Bio::Tools::RNAMotif
Args : -fh/-file for input filename
-motiftag => primary tag used in gene features (default 'misc_binding')
-desctag => tag used for display_name name (default 'rnamotif')
-srctag => source tag used in all features (default 'RNAMotif')
motif_tag
Title : motif_tag
Usage : $obj->motif_tag($newval)
Function: Get/Set the value used for 'motif_tag', which is used for setting the
primary_tag.
Default is 'misc_binding' as set by the global $MotifTag.
'misc_binding' is used here because a conserved RNA motif is capable
of binding proteins (regulatory proteins), antisense RNA (siRNA),
small molecules (riboswitches), or nothing at all (tRNA,
terminators, etc.). It is recommended that this be changed to other
tags ('misc_RNA', 'protein_binding', 'tRNA', etc.) where appropriate.
For more information, see:
http://www.ncbi.nlm.nih.gov/collab/FT/index.html
Returns : value of motif_tag (a scalar)
Args : on set, new value (a scalar or undef, optional)
source_tag
Title : source_tag
Usage : $obj->source_tag($newval)
Function: Get/Set the value used for the 'source_tag'.
Default is 'RNAMotif' as set by the global $SrcTag
Returns : value of source_tag (a scalar)
Args : on set, new value (a scalar or undef, optional)
desc_tag
Title : desc_tag
Usage : $obj->desc_tag($newval)
Function: Get/Set the value used for the query motif. This will be placed in
the tag '-display_name'. Default is 'rnamotif' as set by the global
$DescTag. Use this to manually set the descriptor (motif searched for).
Since there is no way for this module to tell what the motif is from the
name of the descriptor file or the RNAMotif output, this should
be set every time an RNAMotif object is instantiated for clarity
Returns : value of exon_tag (a scalar)
Args : on set, new value (a scalar or undef, optional)
analysis_method
Usage : $obj->analysis_method();
Purpose : Inherited method. Overridden to ensure that the name matches
/RNAMotif/i.
Returns : String
Argument : n/a
next_feature
Title : next_feature
Usage : while($gene = $obj->next_feature()) {
# do something
}
Function: Returns the next gene structure prediction of the RNAMotif result
file. Call this method repeatedly until FALSE is returned.
The returned object is actually a SeqFeatureI implementing object.
This method is required for classes implementing the
SeqAnalysisParserI interface, and is merely an alias for
next_prediction() at present.
Returns : A Bio::Tools::Prediction::Gene object.
Args : None (at present)
next_prediction
Title : next_prediction
Usage : while($gene = $obj->next_prediction()) {
# do something
}
Function: Returns the next gene structure prediction of the RNAMotif result
file. Call this method repeatedly until FALSE is returned.
Returns : A Bio::SeqFeature::Generic object
Args : None (at present)
clean_features
Title : next_prediction
Usage : @list = $obj->clean_features(-10);
Function: Cleans (reduces redundant hits) based on score, position
Returns : a Bio::SeqFeature::Collection object
Args : Pos./Neg. integer (for highest/lowest scoring seqfeature within x bp).
Throws : Error unless digit is entered.