Abstract: The present invention provides a method for obtaining diverse novel genes by inducing somatic cell homologous recombination at genetic loci in somatic cells. By controlling transcription activity of a gene that exists at a genetic locus in a eukaryotic organism cell wherein DNA homologous recombination is occurring at an arbitrary genetic locus, somatic cell homologous recombination is induced between said gene and a gene having a DNA sequence similar to said gene that exists in a region upstream of a transcription promoter, whereby it is possible to obtain diverse novel genes having a plurality of genetic information.

Abstract: A method includes providing a eukaryotic cell including mutant mtDNA in which there is at least one mutation in the mtDNA, allowing the cell to come into contact with an active oxygen species or a chemical species that generates such an active oxygen species in the cell (e.g., hydrogen peroxide) and thereby changing the percentage of mutant mtDNA (mitochondrial genomic DNA) in the cell as a result of the contact. Also featured are cells obtained by the above-described method.

Abstract: The present invention provides a novel method for obtaining diverse antibodies as a result of markedly enhancing the somatic homologous recombination at an antibody locus in immunocytes. By putting immunocytes in which DNA homologous recombination is occurring at an antibody locus (for example, DT40 cells and the like) into contact and the like with histone acetylase inhibitor and the like (for example, trichostatin A and the like), thereby relaxing the chromatin structure at said antibody locus, somatic homologous recombination at an antibody locus is enhanced, and the production of diverse antibody molecules is made possible. The production of antibodies that bind specifically to antigens from cell populations in which the antibody molecules have been diversified by the enhancement of somatic homologous recombination is made possible by using an appropriate selection method (for example, beads coated with antigen and the like).

Abstract: It is an object of the present invention to provide a method, which comprises allowing a eukaryotic cell to come into contact with a reactive oxygen species or a chemical species that generates such a reactive oxygen species in the cell, and thereby changing the percentage of mutant mtDNA (mitochondrial genomic DNA) in the cell, and cells obtained by the above-described method. The present invention relates to a method, which comprises allowing cells to come into contact with a reactive oxygen species by, for example, adding the reactive oxygen species such as hydrogen peroxide to a medium containing the cells, and then culturing the cells under suitable culture conditions, so that the percentage of mtDNA having specific mutation in the cell can be changed. In addition, the present invention also relates to cells, in which the percentage of the mtDNA having specific mutation has been changed by the above-described method.

Abstract: The invention establishes a technology that allows non-specific amplification to be inhibited during nucleic acid amplification in an isothermal amplification reaction, such that the amplification efficiency is increased. The invention is a extreme thermophile single-stranded DNA binding mutant protein, having an amino acid sequence that expresses a function that can contribute to increasing an amplification efficiency of a template nucleic acid in an isothermal amplification reaction system that uses a strand displacement polymerase, and having in its amino acid sequence a mutation site where a mutation involving at least one of deletion, substitution, addition, and insertion of one or more amino acids in amino acid sequence of extreme thermophile single-stranded DNA binding protein has occurred, and a method of use thereof.

Abstract: The present invention relates to a method for increasing genetic recombination frequency in a genomic DNA and a method for inducing genome rearrangement. Specifically, according to the present invention there are provided: the method for increasing genetic recombination frequency in a cell in which genetic recombination takes place at any sites in the genome, comprising causing a restriction enzyme to be expressed in the cell, inducing transient activation of the restriction enzyme, and then introducing 2 or more double strand cleavages into any genomic DNA of the cell, so as to increase the genetic recombination frequency; the method for inducing genome rearrangement through the use of the above method; and cells each prepared through the use of the above 2 methods.

Abstract: The present invention provides a novel method for obtaining diverse antibodies as a result of markedly enhancing the somatic homologous recombination at an antibody locus in immunocytes. By putting immunocytes in which DNA homologous recombination is occurring at an antibody locus (for example, DT40 cells and the like) into contact and the like with histone acetylase inhibitor and the like (for example, trichostatin A and the like), thereby relaxing the chromatin structure at said antibody locus, somatic homologous recombination at an antibody locus is enhanced, and the production of diverse antibody molecules is made possible.

Abstract: A heat-stable RecA mutant protein is obtained by mutation involving either deletion or substitution of at least one amino acid in an amino acid sequence composing an acid region at C-terminal end of a wild type heat-stable RecA protein, and has an improved ability, compared to the wild type heat-stable RecA protein, for contributing to an increase in an amplification specificity of a template nucleic acid in a nucleic acid amplification reaction.

Abstract: The present invention provides a novel method for obtaining diverse antibodies as a result of markedly enhancing the somatic homologous recombination at an antibody locus in immunocytes. By putting immunocytes in which DNA homologous recombination is occurring at an antibody locus (for example, DT40 cells and the like) into contact and the like with histone acetylase inhibitor and the like (for example, trichostatin A and the like), thereby relaxing the chromatin structure at said antibody locus, somatic homologous recombination at an antibody locus is enhanced, and the production of diverse antibody molecules is made possible. The production of antibodies that bind specifically to antigens from cell populations in which the antibody molecules have been diversified by the enhancement of somatic homologous recombination is made possible by using an appropriate selection method (for example, beads coated with antigen and the like).

Abstract: An object of the present invention is to provide a nucleic acid amplification method for amplifying a desired nucleic acid while suppressing amplification of byproducts in a PCR reaction, a reagent kit used for nucleic acid amplification, a method of detecting single nucleotide polymorphism to detect single nucleotide polymorphism by utilizing that amplification of byproducts is suppressed in a PCR reaction, and a reagent kit used for detecting single nucleotide polymorphism. The method of amplifying nucleic acids by PCR is characterized by admixing in a reaction solution, a homologous recombinant protein which contains at least one of a RecA protein derived from Thermus thermophilus, and a modified RecA protein obtained by modification of the RecA protein and having a function similar to that of the RecA protein, and carrying out PCR.

Abstract: An object of the present invention is to provide a nucleic acid amplification method for amplifying a desired nucleic acid while suppressing amplification of byproducts in a PCR reaction, a reagent kit used for nucleic acid amplification, a method of detecting single nucleotide polymorphism to detect single nucleotide polymorphism by utilizing that amplification of byproducts is suppressed in a PCR reaction, and a reagent kit used for detecting single nucleotide polymorphism. The method of amplifying nucleic acids by PCR is characterized by admixing in a reaction solution, a homologous recombinant protein which contains at least one of a RecA protein derived from Thermus thermophilus, and a modified RecA protein obtained by modification of the RecA protein and having a function similar to that of the RecA protein, and carrying out PCR.

Abstract: The present invention relates to a method of selecting a protein specifically binding to a specific ligand. A method of selecting from a diversifying library a protein specifically binding to a ligand of interest, which comprises: a step of allowing proteins existing in the above library to come into contact with the ligand of interest, so as to select proteins binding to the ligand of interest; a step of allowing the obtained proteins to come into contact with a control ligand, so as to determine the presence or absence of the binding ability of the above proteins to the control ligand; and a step of selecting proteins that are determined not to have the binding ability to the control ligand.

Abstract: The present invention relates to a method for increasing genetic recombination frequency in a genomic DNA and a method for inducing genome rearrangement. Specifically, according to the present invention there are provided: the method for increasing genetic recombination frequency in a cell in which genetic recombination takes place at any sites in the genome, comprising causing a restriction enzyme to be expressed in the cell, inducing transient activation of the restriction enzyme, and then introducing 2 or more double strand cleavages into any genomic DNA of the cell, so as to increase the genetic recombination frequency; the method for inducing genome rearrangement through the use of the above method; and cells each prepared through the use of the above 2 methods.

Abstract: The invention establishes a technology that allows non-specific amplification to be inhibited during nucleic acid amplification in an isothermal amplification reaction, such that the amplification efficiency is increased. The invention is a extreme thermophile single-stranded DNA binding mutant protein, having an amino acid sequence that expresses a function that can contribute to increasing an amplification efficiency of a template nucleic acid in an isothermal amplification reaction system that uses a strand displacement polymerase, and having in its amino acid sequence a mutation site where a mutation involving at least one of deletion, substitution, addition, and insertion of one or more amino acids in amino acid sequence of extreme thermophile single-stranded DNA binding protein has occurred, and a method of use thereof.

Abstract: The present invention provides a novel method for obtaining diverse antibodies as a result of markedly enhancing the somatic homologous recombination at an antibody locus in immunocytes. By putting immunocytes in which DNA homologous recombination is occurring at an antibody locus (for example, DT40 cells and the like) into contact and the like with histone acetylase inhibitor and the like (for example, trichostatin A and the like), thereby relaxing the chromatin structure at said antibody locus, somatic homologous recombination at an antibody locus is enhanced, and the production of diverse antibody molecules is made possible.

Abstract: A method of controlling telomere length wherein the method comprises introducing into a cell a DNA encoding Mre11 protein or a DNA encoding a protein comprising Mre11 protein wherein a part of the nuclease domain, the C-terminal domain or the whole thereof is modified or deleted.

Abstract: This invention is to provide a nucleic acid recombination method which enables to carry out precisely homologous recombination of a desired target region, a host cell which enables to carry out precisely homologous recombination of a desired target region, and an expression vector which can be used for the nucleic acid recombination method and the host cell. The nucleic acid recombination method to carry out homologous recombination of a nucleic acid in a host cell employs a host cell which enables the expression and recombination of a RecA-like protein, and enables the expression of a RecX-like protein. And, the nucleic acid recombination method comprises a recombination step of a nucleic acid to carry out homologous recombination of the nucleic acid by the RecA-like protein expressed in the host cell, and a RecA inhibition step to inhibit the activity of the RecA-like protein by expressing the RecX-like protein.

Abstract: The present invention provides a method for obtaining diverse novel genes by inducing somatic cell homologous recombination at genetic loci in somatic cells. By controlling transcription activity of a gene that exists at a genetic locus in a eukaryotic organism cell wherein DNA homologous recombination is occurring at an arbitrary genetic locus, somatic cell homologous recombination is induced between said gene and a gene having a DNA sequence similar to said gene that exists in a region upstream of a transcription promoter, whereby it is possible to obtain diverse novel genes having a plurality of genetic information.

Abstract: The present invention provides the antibody that react with the cleavage product of vimentin, but not with intact vimentin.

Abstract: A method of amplifying a template DNA molecule in an isothermal reaction that can reduce background noise is provided. A method of amplifying a template DNA molecule using a strand-displacing DNA polymerase capable of carrying out isothermal amplification includes a step of conducting an amplification reaction with the addition of a single-strand DNA binding protein (SSB) from an extreme thermophile.