Chimeric nonhuman animal

1 . A method for producing a chimeric non-human animal, which comprises the steps of:

1 ) preparing a pluripotent cell derived from a non-human animal containing a genome wherein a nucleic acid sequence encoding a desired protein is located so that the expression of the desired protein is regulated by the regulatory region of a gene that is expressed in at least a specific cell and/or tissue;

2) obtaining a chimeric embryo by injecting the pluripotent cell prepared in the step I into a host embryo of a non-human animal strain that is deficient in the specific cell and/or tissue;

3) transplanting the chimeric embryo obtained in the step 2 to a foster parent non-human animal of the same species; and

4) selecting a chimeric non-human animal expressing the desired protein in at least the specific cell and/or tissue from offsprings obtained after the transplantation step 3:

2 . The method of claim 1 , wherein the nucleic acid sequence encoding a desired protein is located downstream of the regulatory region of a gene that is expressed in a specific cell and/or tissue.

3 . The method of claim 1 , wherein the nucleic acid sequence encoding a desired protein is located downstream of an internal ribosomal entry site located downstream of the termination codon of a gene that is expressed in a specific cell and/or tissue.

4 . The method of claim 1 , wherein a sequence containing an internal ribosomal entry site and the nucleic acid sequence encoding a desired protein is located between the termination codon and a polyA signal region of a gene that is expressed in a specific cell and/or tissue.

5 . The method of claim 1 , wherein a sequence containing a polyA signal region, a promoter sequence, and the nucleic acid sequence encoding a desired protein is located between the termination codon and a polyA signal region of a gene that is expressed in a specific cell and/or tissue.

6 . The method of claim 5 , wherein the promoter sequence is derived from a gene that is expressed in a specific cell and/or tissue.

7 . The method of claim 1 , wherein a sequence containing a promoter sequence, the nucleic acid sequence encoding a desired protein, and a polyA signal region is located downstream of a polyA signal region of a gene that is expressed in a specific cell and/or tissue.

8 . The method of claim 7 , wherein the promoter sequence is derived from a gene that is expressed in a specific cell and/or tissue.

9 . The method of claim 7 , wherein the distance between the polyA signal region of the gene that is expressed in a specific cell and/or tissue and the promoter sequence is preferably less than 1 Kb.

10 . The method of claim 1 , wherein the pluripotent cell contains both a genome wherein the nucleic acid sequence encoding a desired protein is located so that the expression of the desired protein is regulated by the regulatory region of a gene that is expressed in at least a specific cell and/or tissue, and a genome wherein the allele of the gene that is expressed in the specific cell and/or tissue is inactivated.

11 . The method of claim 1 , wherein the pluripotent cell is an embryonic stem cell.

12 . The method of claim 1 , wherein the chimeric non-human animal is selected from the group consisting of mice, cattle, pigs, monkeys, rats, sheep, goats, rabbits, and hamsters.

13 . The method of claim 1 , wherein the chimeric non-human animal is a mouse.

14 . The method of claim 1 , wherein a combination of a gene that is expressed in a specific cell and/or tissue and the specific cell and/or tissue deficient in a non-human animal strain is selected from the group consisting of the following (1) to (7):

(1) an immunoglobulin light chain or heavy chain gene and a B-lymphocyte;

(2) a T-cell receptor gene and a T-lymphocyte;

(3) a myoglobin gene and a muscle cell;

(4) a crystallin gene and a crystalline lens of an eyeball;

(5) a renin gene and a kidney tissue;

(6) an albumin gene and a liver tissue; and

(7) a lipase gene and a pancreas tissue.

15 . The method of claim 1 , wherein the combination of a gene that is expressed in a specific cell and/or tissue and the specific cell and/or tissue deficient in a non-human animal strain is that of an immunoglobulin light chain κ gene and a B-lymphocyte.

16 . A method for producing a non-human animal expressing a desired protein, which comprises obtaining an offspring capable of expressing the desired protein by crossing the chimeric non-human animal produced by the method of any one of claims 1 to 15 .

17 . A chimeric non-human animal, which is derived from a pluripotent cell derived from a non-human animal containing a genome wherein a nucleic acid sequence encoding a desired protein is located so that the expression of the desired protein is regulated by the regulatory region of a gene that is expressed in a specific cell and/or tissue and a host embryo of a non-human animal strain deficient in the specific cell and/or tissue, and is capable of expressing the desired protein in at least the specific cells and/or tissues.

18 . The chimeric non-human animal of claim 17 , wherein the nucleic acid sequence encoding a desired protein is located downstream of the regulatory region of a gene that is expressed in a specific cell and/or tissue.

19 . The chimeric non-human animal of claim 17 , wherein the nucleic acid sequence encoding a desired protein is located downstream of an internal ribosomal entry site located downstream of the termination codon of a gene that is expressed in a specific cell and/or tissue.

20 . The chimeric non-human animal of claim 17 , wherein a sequence containing an internal ribosomal entry site and the nucleic acid sequence encoding a desired protein is located between the termination codon and a polyA signal region of a gene that is expressed in a specific cell and/or tissue.

21 . The chimeric non-human animal of claim 17 , wherein a sequence containing a polyA signal region, a promoter sequence, and the nucleic acid sequence encoding a desired protein is located between the termination codon and a polyA signal region of a gene that is expressed in a specific cell and/or tissue.

22 . The chimeric non-human animal of claim 21 , wherein the promoter sequence is derived from a gene that is expressed in a specific cell and/or tissue.

23 . The chimeric non-human animal of claim 17 , wherein a sequence containing a promoter sequence, the nucleic acid sequence encoding a desired protein, and a polyA signal region is located downstream of a polyA signal region of a gene that is expressed in a specific cell and/or tissue.

24 . The chimeric non-human animal of claim 23 , wherein the promoter sequence is derived from a gene that is expressed in a specific cell and/or tissue.

25 . The chimeric non-human animal of claim 23 , wherein the distance between the polyA signal region of a gene that is expressed in a specific cell and/or tissue and the promoter sequence is less than 1 Kb.

26 . The chimeric non-human animal of claim 17 , wherein the pluripotent cell contains both a genome wherein the nucleic acid sequence encoding a desired protein is located so that the expression of the desired protein is regulated by the regulatory region of a gene that is expressed in at least a specific cell and/or tissue, and a genome wherein the allele of the gene that is expressed in the specific cell and/or tissue is inactivated.

27 . The chimeric non-human animal of claim 17 , wherein the pluripotent cell is an embryonic stem cell.

28 . The chimeric non-human animal of claim 17 , which is selected from the group consisting of mice, cattle, pigs, monkeys, rats, sheep, goats, rabbits, and hamsters.

29 . The chimeric non-human animal of claim 17 , which is a mouse.

30 . The chimeric non-human animal of claim 17 , wherein a combination of a gene that is expressed in a specific cell and/or tissue and the cell and/or tissue deficient in a non-human animal strain is selected from the group consisting of the following (1) to (7):

(1) an immunoglobulin light chain or heavy chain gene and a B-lymphocyte;

(2) a T-cell receptor gene and a T-lymphocyte;

(3) a myoglobin gene and a muscle cell;

(4) a crystallin gene and a crystalline lens of an eyeball;

(5) a renin gene and a kidney tissue;

(6) an albumin gene and a liver tissue; and

(7) a lipase gene and a pancreas tissue.

31 . The chimeric non-human animal of claim 17 , wherein the combination of a gene that is expressed in a specific cell and/or tissue and the specific cell and/or tissue deficient in a non-human animal strain is that of an immunoglobulin light chain κ gene and a B-lymphocyte.

32 . A method for analyzing the in vivo functions of a desired protein or a gene encoding the desired protein, which comprises comparing the phenotype of the chimeric non-human animal of any one of claims 17 to 31 or an offspring of the chimeric non-human animal capable of expressing the desired protein with that of a corresponding wild-type non-human animal containing no nucleic acid sequence encoding the desired protein, so as to determine differences in these phenotypes.