I-motif DNA I-motif DNA i-motif DNA is a type of deoxyribonucleic acid, discovered in 2018, that is found in the nuclei of human cells. An abbreviation of intercalated motif, the four-strand i-motif is unlike the iconic double helix DNA. I-motifs are four-stranded quadruplex structures formed by cytosine-rich DNA, similar to the G-quadruplex structures that guanine-rich DNA forms. C-rich DNA regions are common in gene regulation portions of the genome. Recently, i-motifs were discovered in human cells and were shown to play a role in cell reproduction. I-motifs have potential applications in nanotechnology and nanomedicine due to their unique pH sensitivity and have
DNA methylation in cancer and predisposes the cell and its descendants to progression to cancer. Another review also indicated an early role for hypermethylation of DNA repair genes in cancer. If a gene necessary for DNA repair is hypermethylated, resulting in deficient DNA repair, DNA damages will accumulate. Increased DNA damage tends to cause increased errors during DNA synthesis, leading to mutations that can give rise to cancer. If hypermethylation of a DNA repair gene is an early step in carcinogenesis, then it may also occur in the normal-appearing tissues surrounding the cancer from which the cancer arose (the field defect). See the table