Description

This track predicts G-quadruplex (G4) forming sites by searching for a specific sequence motif using regular expressions. The motif is defined as four tracts of at least three consecutive guanines (G) separated by loops of 1–7 arbitrary nucleotides (loop length 0–6, without more than two consecutive Gs to avoid motif boundary overlaps), and also recognizes the complementary cytosine (C)-rich pattern to determine strand orientation. Because R-loop formation displaces the non-template DNA strand as single-stranded DNA and R-loop regions frequently exhibit positive GC skew, the exposed guanine-rich single strand is prone to fold into G-quadruplex (G4) structures. Consequently, R-loops and G4s show a certain degree of colocalization. This track serves as one of the genomic features for assessing the reliability of R-loop formation.