Composition and method for sequencing nucleic acid

Abstract

A composition for sequencing DNA is provided and comprises a nuclease and a nuclease-resistant sequencing primer. A method of preparing DNA for sequencing and a method of sequencing DNA are also provided. The method of sequencing DNA can comprise contacting amplification reaction products with the composition under conditions in which excess amplification primer is degraded by the nuclease and the nuclease-resistant sequencing primer is essentially non-degraded.

What is claimed is: 
     
         1 . A method of preparing DNA for sequencing, comprising the steps of
 amplifying the DNA under conditions to produce amplification reaction products, the amplification reaction products comprising excess amplification primer; and   contacting said amplification reaction products with a reaction mixture comprising a nuclease and a nuclease-resistant sequencing primer, under conditions in which the excess amplification primer is degraded by the nuclease and the nuclease-resistant sequencing primer is essentially non-degraded.   
     
     
         2 . The method of  claim 1 , wherein the amplification reaction products further comprise a target amplicon. 
     
     
         3 . The method of  claim 1 , further comprising inactivating the nuclease after the excess amplification primer is degraded by the nuclease. 
     
     
         4 . The method of  claim 3 , wherein inactivating the nuclease comprises heating. 
     
     
         5 . The method of  claim 1 , wherein the nuclease comprises exonuclease I. 
     
     
         6 . The method of  claim 1 , wherein the nuclease-resistant sequencing primer comprises at least one phosphorothioate linkage. 
     
     
         7 . The method of  claim 1 , wherein the nuclease-resistant sequencing primer comprises a phosphorothioate linkage at a terminal 3′ end of the sequencing primer. 
     
     
         8 . A method for sequencing DNA, comprising the steps of:
 amplifying DNA in a first reaction mixture comprising nuclease-sensitive amplification primers to form amplified DNA;   contacting said first reaction mixture of the amplifying step with a second reaction mixture comprising a nuclease and a nuclease-resistant sequencing primer, under conditions in which the nuclease sensitive amplification primers are degraded by the nuclease;   inactivating the nuclease; and   causing the amplified DNA to react in a sequencing reaction under conditions in which the nuclease-resistant sequencing primer primes said sequencing reaction.   
     
     
         9 . The method of  claim 8 , further comprising:
 obtaining results based on the sequencing reaction; and   determining a nucleotide base sequence of the amplified DNA based on the results.   
     
     
         10 . The method of  claim 8 , wherein amplifying DNA comprises polymerase chain reaction amplification. 
     
     
         11 . The method of  claim 8 , wherein the nuclease comprises exonuclease I. 
     
     
         12 . The method of  claim 8 , wherein the nuclease-resistant sequencing primer comprises at least one phosphorothioate linkage. 
     
     
         13 . The method of  claim 12 , wherein the nuclease-resistant sequencing primer comprises a phosphorothioate linkage at a terminal 3′ end. 
     
     
         14 . The method of  claim 8 , wherein inactivating the nuclease comprises heating. 
     
     
         15 . The method of  claim 8 , wherein the sequencing reaction comprises cycle sequencing. 
     
     
         16 . The method of  claim 8 , wherein the second reaction mixture further comprises deoxynucleotide triphosphates, dye-labeled dideoxynucleotide triphosphates, and DNA polymerase. 
     
     
         17 . A composition for sequencing nucleic acid, comprising a polymerase, a nuclease, a nuclease-resistant sequencing primer, deoxynucleotide triphosphates, and dideoxynucleotide triphosphates. 
     
     
         18 . The composition of  claim 17 , further comprising PCR amplification reaction product that comprises non-nuclease-resistant amplification primer. 
     
     
         19 . The composition of  claim 18 , wherein the PCR amplification reaction product further comprises an amplified DNA target sequence. 
     
     
         20 . The composition of  claim 17 , wherein the polymerase is Taq polymerase. 
     
     
         21 . The composition of  claim 17 , wherein the nuclease comprises exonuclease I. 
     
     
         22 . The composition of  claim 17 , wherein the nuclease-resistant primer comprises at least one phosphorothioate linkage. 
     
     
         23 . The composition of  claim 22 , wherein the nuclease-resistant primer comprises a phosphorothioate linkage at a terminal 3′ end of the primer. 
     
     
         24 . The composition of  claim 17 , wherein the nuclease-resistant primer comprises an exonuclease I resistant primer. 
     
     
         25 . The composition of  claim 17 , wherein the dideoxynucleotide triphosphates comprise dye-labeled dideoxynucleotide triphosphates. 
     
     
         26 . The composition of  claim 25 , wherein the dye-labeled dideoxynucleotide triphosphates comprise fluorescent dye-labeled dideoxynucleotide triphosphates.