title: [Improvement and Evaluation on Bisulfite Modification of DNA for DNA Methylation Detection].
abstract: OBJECTIVE
  To establish a rapid and convenient method of DNA modification by bisulfite sodium for the detection of DNA methylation.
  
  
  METHODS
  Through increasing the bisulfite sodium concentration and the temperature of treatment, cutting down the modification time, besides using glassmilk to adsorb the DNA in the purification and recovery, to improve the methods of DNA modification. Efficiency of cytosine converted to thymine in MAGE-A3 gene and DAP-K gene fragments were analyzed by bisulfite sequencing PCR in order to evaluate the DNA modification effect among the improved method, traditional method and kit method.
  
  
  RESULTS
  The operating time of test was shortened to about 3 hours by the improved method; conversion rate of unmethylated cytosine to thymine was over 99%; compared with the traditional method and kit method, there was no significant difference (χ(2) = 0.0564, P > 0.05); the improved method was only for the unmethylated cytosine conversion modification, and there was no significant difference in process of methylated cytosine converted to thymine comparing with the traditional method (χ(2) = 0.0149, P > 0.05).
  
  
  CONCLUSIONS
  The improved method has high efficiency of DNA modification and has no significant effect on excessive modification;meanwhile, it has many advantages such as time-saving and easy to operate etc.
authors.affiliation: ZHANG Zhong-Jing Traditional Chinese Medicine College, Nanyang Institute of Technology, Nanyang 473004, Henan Province, China. E-mail: hnnyyss@163.com.
authors.forename: Song-Shan
authors.initials: SS
authors.lastname: Ye
authors.affiliation: Department of Neurology, The First People's Hospital of Nanyang, Nanyang 473000, Henan Province, China.
authors.forename: Xian-Juan
authors.initials: XJ
authors.lastname: Liu
authors.affiliation: ZHANG Zhong-Jing Traditional Chinese Medicine College, Nanyang Institute of Technology, Nanyang 473004, Henan Province, China.
authors.forename: Jun-Ran
authors.initials: JR
authors.lastname: Hou
authors.affiliation: ZHANG Zhong-Jing Traditional Chinese Medicine College, Nanyang Institute of Technology, Nanyang 473004, Henan Province, China.
authors.forename: Bing-Yu
authors.initials: BY
authors.lastname: Mao
authors.affiliation: Da An Gene Co., Ltd. of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Geng
authors.initials: G
authors.lastname: Qiu
mesh_terms: D003596:Cytosine / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D019175:DNA Methylation; D016133:Polymerase Chain Reaction; D013447:Sulfites / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry
chemical_list: D013447:Sulfites; D003596:Cytosine; D004247:DNA; D013941:Thymine; C009279:sodium bisulfite