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://github.com/bioperl/bioperl-live/issues
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.