Quadfinder: server for identification and analysis of quadruplex-forming motifs in nucleotide sequences

G- quadruplex secondary structures, which play a structural role in repetitive DNA such as telomeres, may also play a functional role at other genomic locations as targetable regulatory elements which control gene expression. The recent interest in application of quadruplexes in biological systems prompted us to develop a tool for the identification and analysis of quadruplex- forming nucleotide sequences especially in the RNA. Here we present Quadfinder, an online server for prediction and bioinformatics of uni-molecular quadruplex- forming nucleotide sequences. The server is designed to be user- friendly and needs minimal intervention by the user, while providing flexibility of defining the variants of the motif. The server is freely available at URL http://miracle.igib.res.in/quadfinder/.