Claims
- 1. A method for obtaining at least one specific DNA sequence related to a target sequence, from a sample comprising a mixed population of a plurality of microbial species, comprising DNA or a mixture of nucleic acids, the method comprising:
a) extracting the DNA or mixture of nucleic acids from said sample; b) hybridizing said DNA or mixture of nucleic acids with a degenerate primer targeted to a single region in said target sequence to synthesize at least one single stranded copy-DNA complementary to a region of said target sequence, said synthesis being primed by said degenerate primer and catalyzed by a DNA-polymerase or a reverse transcriptase; and performing a linear amplification of said at least one single stranded copy-DNA by repeated thermal cycling; c) purifying the single stranded copy-DNA synthesized in step b); d) providing a second primer site to the 3′ end of the single stranded copy-DNA; and e) amplifying the single stranded copy-DNA using a primer pair wherein a first primer comprises at least a part of the degenerate primer sequence and a second primer which is complementary to the 3′ primer site of step d) or is an arbitrary primer; to thereby obtain at least one specific DNA sequence related to said target sequence.
- 2. The method according to claim 1 wherein said second primer site is provided by a method selected from the group consisting of:
a) ligating an anchor sequence to the 3′ end of the purified single stranded copy-DNA; b) producing an anchor sequence by successively adding nucleotides to the 3′ end of the purified single stranded copy-DNA by use of terminal DNA transferase; c) using an arbitrary primer; d) ligating a double stranded oligonucleotide adaptor to a fragmented target DNA, following enzymatic restriction or mechanical treatment prior to generation of single stranded DNA; and e) ligating fragmented targeted DNA following enzymatic restriction or mechanical treatment to vector DNA.
- 3. The method according to claim 2, wherein said ligation of the 3′ anchor sequence of step (a) is catalyzed by a single strand-DNA ligating enzyme such as T4 RNA ligase.
- 4. The method according to claim 1, wherein the degenerate primer of step (b) is additionally used as an arbitrary reverse primer in the amplification reaction of step e).
- 5. The method according to claim 1, wherein the amplification of in step (e) is performed by an amplification method that is dependent on a 5′ located and a 3′ located primer.
- 6. The method according to claim 5, wherein the amplification step is performed by a n amplification method selected from the group consisting of polymerase chain reaction (PCR), nucleic acid sequence based amplification (NASBA) and strand displacement amplification (SDA).
- 7. The method according to claim 5, wherein the amplification step is performed by PCR.
- 8. The method according to claim 1, wherein said degenerated primer comprises a short 3′ degenerate core region in the range from about 8 to about 15 nucleotides, and a longer 5′ consensus clamp region in the range from about 12 to about 30 nucleotides.
- 9. The method according to claim 1, wherein said degenerated primer at its 5′ end is labeled with one member of an affinity pair.
- 10. The method according to claim 9, wherein the affinity pair is selected from the group consisting of biotin—streptavidin, biotin—avidin, digoxigenin—anti-hapten antibody, fluorescein—anti-hapten antibody, lectins—lectin receptor, ion-ion chelators, IgG—protein A, IgG—protein G and magnets—paramagnetic particles.
- 11. The method of claim 1, further comprising amplifying flanking regions to said DNA sequence to obtain a functional gene comprising said DNA sequence.
- 12. The method of claim 11, wherein said flanking regions are amplified with one or more steps of nested PCR reactions.
- 13. The method of claim 1, further comprising screening said sample or a DNA library derived from said sample to isolate a functional gene encoding a protein, using a probe having a sequence which is the same as or complementary to at least a portion of said obtained DNA sequence.
- 14. The method according to claim 1, wherein said sample of DNA or nucleic acids is a complex mixture of nucleic acids extracted from mixed cultures of microorganisms.
- 15. The method according to claim 1, wherein said sample of DNA or nucleic acids is a complex mixture of nucleic acids extracted from an environmental sample.
- 16. The method according to claim 15, wherein the environmental sample is derived from an oligotrophic environment.
- 17. The method according to claim 15, wherein the environmental sample is derived from an extreme environment.
- 18. The method according to claim 15, wherein the environmental sample is derived from a terrestrial geothermal environment.
- 19. The method according to claim 15, wherein the environmental sample is derived from a marine geothermal environment.
- 20. The method according to claim 1 wherein the sample is enriched for a microbial population by maintaining the sample under conditions substantially similar to the environment from which the sample was obtained to thereby expand the microbial population; and allowing a sufficient quantity of a microbial population to expand; whereby the population has been enriched.
- 21. A method for obtaining a functional gene encoding an aminoacylase/amidohydrolase from a sample comprising DNA and/or a mixture of nucleic acids, comprising screening said sample using a nucleic acid probe comprising a nucleotide sequence which is selected from the group consisting of:
a) SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:28, SEQ ID NO:29, SEQ ID NO:30, and SEQ ID NO:31; b) a nucleotide sequence encoding a polypeptide comprising a sequence selected from the group consisting of SEQ ID NO:42, SEQ ID NO:43, SEQ ID NO:44, SEQ ID NO:45, SEQ ID NO:46, SEQ ID NO:47, SEQ ID NO:48, SEQ ID NO:49, SEQ ID NO:50, SEQ ID NO:69, SEQ ID NO:70, SEQ ID NO:71, and SEQ ID NO:72; c) a nucleotide sequence that encode a polypeptide having at least 75% sequence identity to a polypeptide of step b); and d) a nucleotide sequence that is complementary to a nucleotide sequences of step a), b), or c).
- 22. A method for obtaining a functional gene encoding an amylase from a sample comprising DNA and/or a mixture of nucleic acids, comprising screening said sample using a nucleic acid probe comprising a nucleotide sequence selected from the group consisting of:
a) SEQ ID NO:10, SEQ ID NO:11, SEQ ID NO:12, SEQ ID NO:13, SEQ ID NO:14, SEQ ID NO:15, SEQ ID NO:16, SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:20, SEQ ID NO:21, SEQ ID NO:22, SEQ ID NO:23, SEQ ID NO:24, SEQ ID NO:25, SEQ ID NO:26, and SEQ ID NO:27; b) a nucleotide sequence encoding a polypeptide comprising a sequence from the group of SEQ ID NO:51, SEQ ID NO:52, SEQ ID NO:53, SEQ ID NO:54, SEQ ID NO:55, SEQ ID NO:56, SEQ ID NO:57, SEQ ID NO:58, SEQ ID NO:59, SEQ ID NO:61, SEQ ID NO:62, SEQ ID NO:63, SEQ ID NO:64, SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, and SEQ ID NO:68; c) a nucleotide sequence that encodes a polypeptide having at least 65% sequence identity to a polypeptide sequence listed in b); and d) a nucleotide sequence that is complementary to a sequences of step a), b), c).
- 23. A method for obtaining a functional gene encoding an amylase from a sample comprising DNA and/or a mixture of nucleic acids, comprising screening said sample using a nucleic acid probe comprising a nucleotide sequence from the group consisting of SEQ ID NO: 19; sequences encoding the polypeptide described by SEQ ID NO:60; sequences encoding polypeptides having at least 80% sequence identity to SEQ ID NO:60; and sequences that are complementary to any of said sequences.
- 24. An isolated nucleic acid molecule having a nucleic acid sequence which is part of a gene encoding for an aminoacylase/amidohydrolase, selected from the group consisting of:
a) SEQ ID NO:1 and SEQ ID NO:2; SEQ ID NO:3; SEQ ID NO:4; SEQ ID NO:5; SEQ ID NO:6; SEQ ID NO:7; SEQ ID NO:8; SEQ ID NO:9; SEQ ID NO:29; and SEQ ID NO:30; b) sequences encoding a polypeptide comprising a sequence from the group consisting of SEQ ID NO:42, SEQ ID NO:43, SEQ ID NO:44, SEQ ID NO:45, SEQ ID NO:46, SEQ ID NO:47, SEQ ID NO:48, SEQ ID NO:49, SEQ ID NO:50, SEQ ID NO:70, and SEQ ID NO:71; c) and sequences encoding polypeptides having at least 65% sequence identity with a polypeptide encoded by any of said sequences; and d) sequences that are complementary to any of said nucleotide sequences of a)-c).
- 25. An isolated nucleic acid molecule having a nucleic acid sequence which is part of a gene encoding an aminoacylase/amidohydrolase, selected from the group consisting of SEQ ID NO:28 and SEQ ID NO:31; and sequences encoding polypeptides having at least 75% sequence identity with a sequence from SEQ ID NO:69 and SEQ ID NO:72.
- 26. An isolated nucleic acid molecule encoding an aminocylase/amidohyrolase, comprising a nucleic acid sequence of claim 24.
- 27. An isolated nucleic acid molecule encoding an aminocylase/amidohyrolase, comprising a nucleic acid sequence of claim 25.
- 28. An isolated polypeptide encoded by the sequence of claim 26.
- 29. An isolated polypeptide encoded by the sequence of claim 27.
- 30. An isolated nucleic acid molecule having a nucleic acid sequence which is part of a gene encoding for an amylase, said sequence selected from the group consisting of:
a) SEQ ID NO:10, SEQ ID NO:11, SEQ ID NO:12, SEQ ID NO:13, SEQ ID NO:14, SEQ ID NO:15, SEQ ID NO:16, SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:20, SEQ ID NO:21, SEQ ID NO:22, SEQ ID NO:23, SEQ ID NO:24, SEQ ID NO:25, SEQ ID NO:26, and SEQ ID NO:27; b) sequences encoding a polypeptide comprising a sequence from the group of SEQ ID NO:51, SEQ ID NO:52, SEQ ID NO:53, SEQ ID NO:54, SEQ ID NO:55, SEQ ID NO:56, SEQ ID NO:57, SEQ ID NO:58, SEQ ID NO:59, SEQ ID NO:61, SEQ ID NO:62, SEQ ID NO:63, SEQ ID NO:64, SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, and SEQ ID NO:68; c) sequences encoding for polypeptides having at least 65% sequence identity to a polypeptide sequence listed in b); and d) sequences that are complementary to any of said sequences of a)-c).
- 31. An isolated nucleic acid sequence which sequence is part of a gene encoding for an amylase, said sequence from the group consisting of SEQ ID NO:19; and sequences encoding for the polypeptide described by SEQ ID NO: 60; and sequences encoding for polypeptides having at least 80% sequence identity to SEQ ID NO:60.
- 32. An isolated nucleic acid molecule encoding for an amylase, comprising a nucleic acid sequence of claim 30.
- 33. An isolated nucleic acid molecule encoding for an amylase, comprising a nucleic acid sequence of claim 31.
- 34. An isolated polypeptide encoded by the nucleic acid molecule of claim 32.
- 35. An isolated polypeptide encoded by the nucleic acid molecule of claim 33.
Priority Claims (1)
Number |
Date |
Country |
Kind |
6372 |
May 2002 |
IS |
|
RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. §119 or 365 to Iceland Application No. 6372, filed May 3, 2002. The entire teachings of the above application are incorporated herein by reference.