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 DNA methylation in cancer DNA methylation in cancer plays a variety of roles, helping to change the healthy regulation of gene expression to a disease pattern. All mammalian cells descended from a fertilized egg (a zygote) share a common DNA sequence (except for new mutations in some lineages). However, during development and formation of different tissues epigenetic factors change. The changes include histone modifications, CpG island methylations and chromatin reorganizations which can cause the stable silencing or activation of particular genes. Once differentiated tissues are formed, CpG island methylation is generally stably inherited from one cell division to the next