Research On Selective Fluorescence Labeling Aldehydes Of DNA

Aldehyde is an important group of natural nucleotide modification in DNA,which is of great significance in the reasearch of epigenetics.These aldehydemodified nucleobases,including 5-formylcytosine(5fC),5-formyluracil(5fU)and abasic site(AP),play a key role in regulating gene expression in eukaryotes and prokaryotes,and their modification level is closely related to disease.There are some connections among 5fC,5fU and AP,such as participating in the active demethylation of DNA,altering the structure and stability of DNA to cause DNA damage,interacting with proteins to form DNA-protein cross-links and so on.Therefore,we take three nucleobases as the common research objects,and devote ourselves to labeling and detecting them simultaneously with small-molecule fluorescent probes.In this thesis,naphthalimide amino and naphthalimide hydroxylamine probes targeting an aldehyde group were designed and synthesized.By comparing their reactivity and stability with three different nucleobase monomers respectively,we finally selected naphthalimide hydroxylamine as the better probe.For the first time,we have selectively labeled all natural aldehydes groups contained in DNA,including 5fC,5fU and AP.The probe has no effect on other groups modified nucleobases,such as hydroxymethyl,methyl and so on.It shows a high specificity to aldehydes.The fluorescence properties of the products were studied in detail,and the reactivity of hydroxylamine towards aldehydes in DNA was discussed.It provides an important reference for the design of selectively labelling modified DNA.It is hoped that the probe can be used to detect aldehydes in vivo in the future.