title: A new method to evaluate trinucleotide repeats length polymorphism.
abstract: Trinucleotide repeats (TNRs) are involved in a number of debilitating diseases and disorders, the length of which usually indicates disease severity at gene level. Herein we have developed a novel fluorescent method in this work to evaluate TNRs length polymorphism based on its DNA secondary structure with doxorubicin (Dox) as fluorescent probe. This new method makes use of the fact that TNRs rich in guanine (G) and cytosine (C) are susceptible to forming stable intramolecular structures, resulting in the formation of double-stranded 5'-GC-3' or 5'-CG-3' sequences. So, intercalating of these sequences by Dox, fluorescence quenching of Dox occurs. Consequently, the length polymorphism of TNRs can be evaluated. Taking the study of CAG for an example, a linear relationship between fluorescence intensity and the sequences ranging from 10 to 35 CAG repeats has been obtained, and the assay of the TNRs length polymorphism for PCR products has been realized. Therefore, without the necessity to introduce fluorophores and quenchers by chemical modifications, this new method is simple, cost-effective and convenient to be operated, so it may hold great promise in the diagnosis of diseases arouse from the triplet expansion.
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, Nanjing University, Nanjing 210093, PR China.
authors.forename: Limin
authors.initials: L
authors.lastname: Ning
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, Nanjing University, Nanjing 210093, PR China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, Nanjing University, Nanjing 210093, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Gao
authors.affiliation: Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China.
authors.forename: Shan
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, Nanjing University, Nanjing 210093, PR China; Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444 , PR China. Electronic address: genxili@nju.edu.cn.
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D004317:Doxorubicin / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D018911:Trinucleotide Repeats
chemical_list: D005456:Fluorescent Dyes; D004317:Doxorubicin
keywords: Doxorubicin; Fluorescence; Length polymorphism; Secondary structure; Trinucleotide repeats