title: [Subtractive SELEX using agar beads for screening DNA aptamers with specific affinity to HIV gp41 antigen].
abstract: OBJECTIVE
  To obtain DNA aptamers with a highly specific affinity to HIV gp41 antigen using SELEX screening for detection of HIV.
  
  
  METHODS
  The specific DNA aptamers of HIV gp41 antigen were screened from the double-stranded DNA derived from the single-stranded DNA (ssDNA) library with agarose beads as the supportive medium and HIV gp41 antigen as the target molecule using SELEX technique and real-time quantitative PCR.
  
  
  RESULTS
  The secondary ssDNA library obtained after 6 rounds of screening was amplified by PCR to obtain dsDNA. The dsDNA was linked with pMDTM18-T vector, cloned and sequenced to obtain 4 aptamers of HIV gp41 antigen. The affinities of the 4 aptamers (Kd) all reached the nanomolar level. Among the 4 aptamers, the No.15 aptamer showed the strongest affinity. Specificity analysis of the aptamers revealed that all these 4 aptamers had specific affinity to HIV gp41 antigen with no affinity to other non-specific proteins.
  
  
  CONCLUSIONS
  We successfully obtained DNA aptamers with highly specific affinity to the HIV gp41 antigen from random single-stranded oligonucleotide library, and the obtained aptamers have the ability to antagonize HIV gp41 antigen.
authors.affiliation: Department of Biological Engineering, College of Environment & Chemical Engineering, Department of Internal Medicine, Yanshan University, Qinhuangdao 066004, China. E-mail: thebestlikun@163.com.
authors.forename: Kun
authors.initials: K
authors.lastname: Li
authors.forename: Chen-Lin
authors.initials: CL
authors.lastname: Xiu
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Gao
authors.forename: Ming
authors.initials: M
authors.lastname: Shi
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhai
mesh_terms: D000362:Agar; D052157:Aptamers, Nucleotide; D001483:Base Sequence; D004247:DNA; D004277:DNA, Single-Stranded; D015723:Gene Library; D015700:HIV Envelope Protein gp41 / Q000032:analysis*; D015658:HIV Infections; D006801:Humans; D052156:SELEX Aptamer Technique; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D004277:DNA, Single-Stranded; D015700:HIV Envelope Protein gp41; C514787:gp41 protein, Human immunodeficiency virus 1; D000362:Agar; D004247:DNA