Method for detecting activity of terminal deoxynucleotidyl transferase on basis of single quantum dot

Abstract

The invention discloses a method for detecting activity of terminal deoxynucleotidyl transferase o on the basis of a single quantum dot. A nano sensor adopted by the method comprises a capture probe,a DNA (deoxyribonucleic acid) primer, a quantum dot QD, and a nucleotide excision enzyme, wherein the capture probe comprises Cy5, biotin and single-stranded DNA1; a 3' terminal of the single-strandedDNA1 is connected with Cy5; a 5' terminal of single-stranded DNA1 is connected with the biotin; the quantum dot QD is a streptavidin bound quantum dot; the capture probe is modified to the surface ofthe quantum dot QD by a streptavidin-biotin interaction; the DNA primer is a DNA sequence; deoxynucleotide can be added to the 3' terminal of the DNA sequence by the action of terminal deoxynucleotidyl transferase for polymerization and extension to form single-stranded DNA2; single-stranded DNA2 can be hybridized with single-stranded DNA1 to form double-stranded DNA; the nucleotide excision enzyme is an enzyme capable of digesting single-stranded DNA1 in the double-stranded DNA from a 3' hydroxyl terminal. The nano sensor can simply, quickly and sensitively detect the activity of terminal deoxynucleotidyl transferase.

Description

technical field [0001] The invention belongs to the technical field of biological analysis, and relates to a method for detecting terminal deoxynucleotidyl transferase activity based on a single quantum dot. Background technique [0002] Terminal deoxynucleotidyl transferase (TdT) is an endonuclease that can randomly introduce nucleotides into the 3'-hydroxyl ( 3'-OH) end. By adding non-template nucleotides (N regions), terminal deoxynucleotides to variable (V), dependent (D) and junctional (J) exon regions of T and B cell receptor genes in T and B cells Transferase (TdT) can add gene fragments in the process of immunoglobulin heavy chain gene recombination, generate various forms of connection, and make a great contribution to the diversity of antigens and antibodies. The activity of terminal deoxynucleotidyl transferase (TdT) is inhibited in most human cells, but in acute lymphoblastic leukemia (ALL) cells (thymus-dependent cell line of acute lymphoblastic leukemia (ALL)...

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Problems solved by technology

However, the above methods still have some unavoidable shortcomings, such as low detection sensitivity, complicated material synthesis and complex chemical reactions, etc.

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