Title
A structure-based flexible search method for motifs in RNA.
Abstract
The discovery of non-coding RNA (ncRNA) motifs and their role in regulating gene expression has recently attracted considerable attention. The goal is to discover these motifs in a sequence database. Current RNA motif search methods start from the primary sequence and only then take into account secondary structure considerations. One can think of developing a flexible structure-based motif search method that will filter datasets based on secondary structure first, while allowing extensive primary sequence factors and additional factors such as potential pseudoknots as constraints. Since different motifs vary in structure rigidity and in local sequence constraints, there is a need for algorithms and tools that can be fine-tuned according to the searched RNA motif, but differ in their approach from the RNAMotif descriptor language. We present an RNA motif search tool called STRMS (Structural RNA Motif Search), which takes as input the secondary structure of the query, including local sequence and structure constraints, and a target sequence database. It reports all occurrences of the query in the target, ranked by their similarity to the query, and produces an html file that displays graphical images of the predicted structures for both the query and the candidate hits. Our tool is flexible and takes into account a large number of sequence options and existence of potential pseudoknots as dictated by specific queries. Our approach combines pre-folding and an O(m n) RNA pattern matching algorithm based on subtree homeomorphism for ordered, rooted trees. An O(n(2) log n) extension is described that allows the search engine to take into account the pseudoknots typical to riboswitches. We employed STRMS in search for both new and known RNA motifs (riboswitches and tRNAs) in large target databases. Our results point to a number of additional purine bacterial riboswitch candidates in newly sequenced bacteria, and demonstrate high sensitivity on known riboswitches and tRNAs. Code and data are available at www.cs.bgu.ac.il/vaksler/STRMS.
Year
DOI
Venue
2007
10.1089/cmb.2007.0061
JOURNAL OF COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
algorithm,energy minimization,riboswitch,RNA search,secondary structure,subtree homeomorphism,tRNA
RNA,Biology,Riboswitch,Transfer RNA,Gene expression,Bioinformatics,Protein secondary structure,Non-coding RNA
Journal
Volume
Issue
ISSN
14.0
7
1066-5277
Citations 
PageRank 
References 
3
0.41
17
Authors
4
Name
Order
Citations
PageRank
Isana Veksler-Lublinksy1122.89
Michal Ziv-Ukelson251436.49
Danny Barash326524.21
Klara Kedem41291251.41