Nucleic acid special structure
This class of nucleic acid includes DNA or RNA forming duplex hairpin, stem-loop, and triplex nucleic acid structure. An RNA or DNA hairpin is secondary structure form by folding of nucleic acids and containing mismatches and bulges and terminal loops. These RNA hairpins or stem loop forms in-vivo by transcription of an inverted repeat DNA . RNA hairpins regulates gene expression in cis or trans, i.e. an RNA hairpin within an RNA molecule can regulate just that molecule (cis) or it can induce effects on other RNAs or pathways (trans). Hairpins serve as binding sites for a variety of proteins, act as substrates for enzymatic reactions as well as display Intrinsic enzymatic activities Hairpin RNA can be recognition motifs to cellular proteins and cause deregulation by sequestration of cellular protein. For example CGG hairpin RNA in FMR1 sequester several protein in sequence specific manner and cause Fragile- X syndrome due to loss of protein function or gain of RNA function.