QuadDB
A simple published algorithm [ref] may be used to locate putative quadruplex sequences (PQSs) in genomic data. The algorithm is based on the Folding rule, derived from various considerations: strand stoichiometry; the number of stacked tetrads in the quadruplex core; the presence of mutations or deletions; and the length and composition of loops. The Folding rule states that "A sequence of the form d( G 3+ N1-7 G 3+ N1-7 G 3+ N1-7 G 3+) will fold into a quadruplex under near-physiological conditions".
Quadparser
Quadparser, a program by Simon Rodgers and Julian Huppert, is developed based on the Folding rule mentioned above.
QuadDB data search
Is it has been shown that G-quadruplexes are present in very high numbers in gene promoters [ref], where they may be involved in regulating gene expression. Furthermore, G-quadruplexes in untranslated region (UTRs) may also regulate translation [ref]. For convenience, we are providing a database search feature for PQSs predicted in the promoter and UTRs in the human genome.
QuadDB data download
For those that may be interested in G-quadruplexes in other regions in the human genome, or G-quadruplexes in other species, we are also providing links to download the full list of G-quadruplexes predicted for the a selected number of popular genomes, in various build versions.
Download G-Quadruplexes Data Here
Distributed Annotation System (DAS)
Distributed Annotation System (DAS) is simple data accessing protocol for annotation on biological sequences. Further information on DAS are available here. Here we provide a list G-Quadruplex data in DAS compatible format, which is particularly useful for displaying G-Quaduplex location data in the Ensembl browser
Website provided as a service to the quadruplex community by Han-Min Wong, Simon Rodgers and Julian Huppert, University of Cambridge.
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