title: Spatial preferences of microRNA targets in 3' untranslated regions.
abstract: BACKGROUND
  MicroRNAs are an important class of regulatory RNAs which repress animal genes by preferentially interacting with complementary sequence motifs in the 3' untranslated region (UTR) of target mRNAs. Computational methods have been developed which can successfully predict which microRNA may target which mRNA on a genome-wide scale.
  
  
  RESULTS
  We address how predicted target sites may be affected by alternative polyadenylation events changing the 3'UTR sequence. We find that two thirds of targeted genes have alternative 3'UTRs, with 40% of predicted target sites located in alternative UTR segments. We propose three classes based on whether the target sites fall within constitutive and/or alternative UTR segments, and examine the spatial distribution of predicted targets in alternative UTRs. In particular, there is a strong preference for targets to be located in close vicinity of the stop codon and the polyadenylation sites.
  
  
  CONCLUSIONS
  The transcript diversity seen in non-coding regions, as well as the relative location of miRNA target sites defined by it, has a potentially large impact on gene regulation by miRNAs and should be taken into account when defining, predicting or validating miRNA targets.
authors.affiliation: Institute for Genome Sciences and Policy, Departments of Biostatistics & Bioinformatics and Computer Science, Duke University, Durham, NC 27708, USA. bmajoros@duke.edu <bmajoros@duke.edu>
authors.forename: William H
authors.initials: WH
authors.lastname: Majoros
authors.forename: Uwe
authors.initials: U
authors.lastname: Ohler
mesh_terms: D020413:3' Untranslated Regions / Q000378:metabolism*; D000465:Algorithms; D017398:Alternative Splicing / Q000235:genetics*; D019295:Computational Biology / Q000379:methods*; D005786:Gene Expression Regulation / Q000235:genetics*; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; D035683:MicroRNAs