Formation of parallel four-stranded complexes by guanine-rich motifs in DNA and its implications for meiosis

We have discovered that single-stranded DNA containing short guanine-rich motifs will self-associate at physiological salt concentrations to make four-stranded structures in which the strands run in parallel fashion. We believe these complexes are held together by guanines bonded to each other by Hoogsteen pairing. Such guanine-rich sequences occur in immunoglobulin switch regions¹, in gene promoters^2,3, and in chromosomal telomeres⁴. We speculate that this self-recognition of guanine-rich motifs of DNA serves to bring together, and to zipper up in register, the four homologous chromatids during meiosis.