Mutagenesis methods and compositions
First Claim
1. A method for introducing a plurality of mutations to a nucleic acid construct comprising a target sequence, a first marker sequence encoding a first protein having an inoperable first marker activity, and a second marker sequence encoding a second protein having an operable second marker activity, said method comprising the steps of:
- (a) annealing to a single-stranded form of said nucleic acid constructa first oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said first oligonucleotide is selected so as to change a nucleotide at a first position of said nucleic acid construct where said first position is within said target sequence, and to introduce or remove a first restriction site at a second position of said nucleic acid construct;
a second oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said second oligonucleotide is selected so as to change one or more nucleotides in said first marker sequence to produce a mutated first marker sequence in a manner which results in an operable first marker activity; and
a third oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said third oligonucleotide is selected so as to change one or more nucleotides in said second marker sequence to produce a mutated second marker sequence in a manner which results in an inoperable second marker activity, thereby forming a primary annealed product;
(b) transforming a host cell with said primary annealed product;
(c) screening or selecting progeny of transformed host cells having said operable first marker activity;
(d) identifying progeny screened or selected and containing a mutated nucleic acid construct containing a mutated target sequence and having said introduced or removed first restriction site;
(e) annealing to a single-stranded form of said mutated nucleic acid constructa fourth oligonucleotide having a sequence substantially complementary to a portion of said mutated nucleic acid construct, wherein the sequence of said fourth oligonucleotide is selected so as to change a nucleotide at a first position of said mutated nucleic acid construct where said first position is within said mutated target sequence, and to introduce or remove a second restriction site at a second position of said mutated nucleic acid construct;
a fifth oligonucleotide having a sequence substantially complementary to a portion of said mutated nucleic acid construct, wherein the sequence of said fifth oligonucleotide is selected so as to restore said first marker sequence in a manner which results in said inoperable first marker activity; and
a sixth oligonucleotide having a sequence substantially complementary to a portion of said mutated nucleic acid construct, wherein the sequence of said sixth oligonucleotide is selected so as to restore said second marker sequence in a manner which results in said operable second marker activity, thereby forming a secondary annealed product;
(f) transforming a host cell with said secondary annealed product;
(g) screening or selecting progeny of transformed host cells having said operable second marker activity; and
(h) identifying progeny screened or selected and containing a further mutated nucleic acid construct having said introduced or removed second restriction site.
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Accused Products
Abstract
Methods and reagents for oligonucleotide-directed mutagenesis of a target nucleic acid are provided. In these methods a mutagenic oligonucleotide introduces a desired mutation at one site and, at a second site, introduces or eliminates a restriction site, allowing one to screen for the desired mutation by restriction analysis. Also provided are vectors and kits for performing such mutagenesis methods.
16 Citations
12 Claims
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1. A method for introducing a plurality of mutations to a nucleic acid construct comprising a target sequence, a first marker sequence encoding a first protein having an inoperable first marker activity, and a second marker sequence encoding a second protein having an operable second marker activity, said method comprising the steps of:
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(a) annealing to a single-stranded form of said nucleic acid construct a first oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said first oligonucleotide is selected so as to change a nucleotide at a first position of said nucleic acid construct where said first position is within said target sequence, and to introduce or remove a first restriction site at a second position of said nucleic acid construct; a second oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said second oligonucleotide is selected so as to change one or more nucleotides in said first marker sequence to produce a mutated first marker sequence in a manner which results in an operable first marker activity; and a third oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said third oligonucleotide is selected so as to change one or more nucleotides in said second marker sequence to produce a mutated second marker sequence in a manner which results in an inoperable second marker activity, thereby forming a primary annealed product; (b) transforming a host cell with said primary annealed product; (c) screening or selecting progeny of transformed host cells having said operable first marker activity; (d) identifying progeny screened or selected and containing a mutated nucleic acid construct containing a mutated target sequence and having said introduced or removed first restriction site; (e) annealing to a single-stranded form of said mutated nucleic acid construct a fourth oligonucleotide having a sequence substantially complementary to a portion of said mutated nucleic acid construct, wherein the sequence of said fourth oligonucleotide is selected so as to change a nucleotide at a first position of said mutated nucleic acid construct where said first position is within said mutated target sequence, and to introduce or remove a second restriction site at a second position of said mutated nucleic acid construct; a fifth oligonucleotide having a sequence substantially complementary to a portion of said mutated nucleic acid construct, wherein the sequence of said fifth oligonucleotide is selected so as to restore said first marker sequence in a manner which results in said inoperable first marker activity; and a sixth oligonucleotide having a sequence substantially complementary to a portion of said mutated nucleic acid construct, wherein the sequence of said sixth oligonucleotide is selected so as to restore said second marker sequence in a manner which results in said operable second marker activity, thereby forming a secondary annealed product; (f) transforming a host cell with said secondary annealed product; (g) screening or selecting progeny of transformed host cells having said operable second marker activity; and (h) identifying progeny screened or selected and containing a further mutated nucleic acid construct having said introduced or removed second restriction site. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A kit for introducing one or more mutations to a nucleic acid construct comprising:
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(a) said nucleic acid construct comprising a ColE1 origin of replication, a polylinker within a lacZ gene for inserting a target sequence, a first marker sequence encoding a first protein having an inoperable first marker activity, and a second marker sequence encoding a second protein having an operable second marker activity; (b) a first oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said first oligonucleotide is selected so as to change one or more nucleotides in said first marker sequence to produce a mutated first marker sequence in a manner which results in an operable first marker activity; (c) a second oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said second oligonucleotide is selected so as to change one or more nucleotides in said second marker sequence to produce a mutated second marker sequence which results in an inoperable second marker activity; (d) a third oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said third oligonucleotide is selected so as to restore said first marker sequence in a manner which results in said inoperable first marker activity; (e) a fourth oligonucleotide having a sequence substantially complementary to a portion of said nucleic acid construct, wherein the sequence of said fourth oligonucleotide is selected so as to restore said second marker sequence in a manner which results in said operable second marker activity; (f) a DNA polymerase; (g) deoxyribonucleotides; (h) a DNA ligase; and (i) buffers suitable for activity of said DNA polymerase and said DNA ligase. - View Dependent Claims (12)
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Specification