Advances in chemical modifications in DNA and role in therapeutics

This book describes about the higher order structures of DNA mainly i-motif and G-quadruplex. Sequences with the potential to form G-quadruplexes and i-motifs are sequestered throughout genome mainly in the promoters of oncogenes and human telomeric DNA and forms intramolecular tetraplex structure during the regulation of oncogene expression at the transcription level. The two important epigenetic markers in the human genome, 5-methylcytosine (mC) and 5-hydroxymethyl cytosine (hmC), are involved in gene regulation processes. This book also takes into account the various aspects of the guanine rich called G-quadruplex structure of the DNA which are formed in the promoter region of a regulator gene called c-myc. Various ligands and proteins help in stabilizing/ destabilizing the G-quadruplex structure present in the regulator gene but a mutated version of the c-myc is seen during cancer which leads to altered functions and expression of transcription protein leading to unregulated cell growth and proliferation. Thus, G-quadruplexes help in regulation of the telomerase enzyme activity and can pave a way for the anti cancer drugs which are the need of the hour.