Marker for undifferentiated state of cell and composition and method for separation and preparation of stem cells

• US 20060288431A1
• Filed: 02/12/2004
• Published: 12/21/2006
• Est. Priority Date: 02/13/2003
• Status: Abandoned Application

• Current Assignee: Kyoto University, Masako Tada, Norio Nakatsuji, ReproCELL Inc., Takashi Tada
• Original Assignee: Kyoto University, Masako Tada, Norio Nakatsuji, ReproCELL Inc., Takashi Tada
• Inventors: Tada, Takashi, Tada, Masako, Nakatsuji, Norio
• Application Number:
  US10/545,368
• Publication Number:
  US 20060288431A1
• Time in Patent Office: Days
• US Class Current: 800/8
• CPC Class Codes: C07K 14/47 from mammals
• CPC Class Codes: C12N 2510/00 Genetically modified cells
• CPC Class Codes: C12N 5/0607 Non-embryonic pluripotent stem cells, e.g. MASC induced pluripotent stem cells C12N5/0696

Abstract

A gene is provided, which can be used as a marker for determining whether a certain cell, particularly an undifferentiated cell including a tissue stem cell, has pluripotency or an undifferentiated state. The gene is called Stm and includes a Stm1 gene, which is expressed specifically in a cell under an undifferentiated state if the cell has pluripotency. A kit for determining a differentiated state of a cell is also provided. The kit comprises (a) an agent capable of reacting specifically with a Stm gene or a Stm gene product; and (b) means for determining whether or not the Stm gene is expressed in the cell.

Claims

1. A nucleic acid molecule, comprising:

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity.

2. A nucleic acid molecule according to claim 1, wherein the nucleic acid molecule is at least 10 contiguous nucleotides in length.

3. A nucleic acid molecule according to claim 1, wherein the nucleic acid molecule has a sequence different from a sequence set forth in SEQ ID NO. 7 or 9 or a corresponding sequence in a corresponding nucleic acid sequence of Stm2 in at least one position in SEQ ID NO. 1, 3, 5 or 29.

4. A nucleic acid molecule according to claim 3, wherein a portion having the different sequence may be digested with a restriction enzyme.

5. A nucleic acid molecule according to claim 1, comprising a sequence set forth in SEQ ID NO. 1, 3, 5 or 29.

7. An agent, which is specific to a nucleic acid molecule according to claim 1.

8. An agent according to claim 7, wherein the agent does not react specifically with a nucleic acid molecule of a Stm2 gene having a sequence set forth in SEQ ID NO. 7 or 9, or a corresponding nucleic acid sequence thereof.

9. An agent according to claim 7, wherein the agent is selected from the group consisting of a nucleic acid molecule, a polypeptide, a lipid, a sugar chain, a low molecular weight organic molecule, and a composite molecule thereof.

10. An agent according to claim 7, wherein the agent is a nucleic acid molecule of at least 8 contiguous nucleotides in length.

11. An agent according to claim 7, wherein the agent is a nucleic acid molecule and is used as a primer.

12. An agent according to claim 7, wherein the agent is used as a probe.

13. An agent according to claim 7, wherein the agent is labeled or labelable.

14. An agent according to claim 13, wherein the label is used in a technique selected from the group consisting of fluorescence, phosphorescence, chemiluminescence, radiation, enzyme-substrate reaction, and antigen-antibody reaction.

26. An expression cassette, comprising a nucleic acid molecule according to claim 1.

27. A vector, comprising a nucleic acid molecule according to claim 1.

28. A vector according to claim 27, further comprising a control sequence operably linked to the nucleic acid molecule.

29. A vector according to claim 28, wherein the control sequence induces expression of the nucleic acid molecule.

30. A vector according to claim 28, further comprising a sequence encoding a selectable marker.

31. A cell, comprising a nucleic acid molecule according to claim 1.

32. A cell, comprising a nucleic acid molecule according to claim 1 in a manner which allows for expression of the nucleic acid molecule.

33. A cell, comprising a nucleic acid molecule according to claim 1 in a manner which allows for expression of the nucleic acid molecule and having a desired genomic sequence.

34. An animal tissue, comprising a nucleic acid molecule according to claim 1.

35. An animal, comprising a nucleic acid molecule according to claim 1.

36. A composition, comprising a concentrated cell comprising a nucleic acid molecule according to claim 1.

6. A nucleic acid molecule, comprising:

(a) a polynucleotide having a base sequence of positions 1037 to 1607 or 244 to 1126 set forth in SEQ ID NO. 3 or a base sequence in corresponding positions, or a fragment thereof;

(b) a polynucleotide hybridizable to the polynucleotide of (a) under stringent conditions, and encoding a polypeptide biological activity;

or

(c) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides of (a) to (b) or a complementary sequence thereof, and encoding a polypeptide having biological activity.

15. A polypeptide, comprising:

(a) a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(b) a polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion, and wherein the variant polypeptide has biological activity;

(c) a polypeptide encoded by a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29;

(d) a polypeptide being a species homolog of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30;

or

(e) a polypeptide having at least 70% identity to anyone of the polypeptides of (a) to (d) and having biological activity.

16. A polypeptide according to claim 15, wherein the polypeptide has an amino acid sequence having at least 3 contiguous amino acids.

17. A polypeptide according to claim 15, wherein the polypeptide has a sequence different from a sequence set forth in SEQ ID NO. 8 or 10 or a corresponding sequence in a corresponding amino acid sequence of Stm2 in at least one position in SEQ ID NO. 2, 4, 6 or 30.

18. A polypeptide according to claim 17, wherein a portion having the different sequence may be digested with a restriction enzyme.

20. An agent, which is specific to a nucleic acid molecule according to claim 15.

21. An agent according to claim 20, wherein the agent is selected from the group consisting of a nucleic acid molecule, a polypeptide, a lipid, a sugar chain, a low molecular weight organic molecule, and a composite molecule thereof.

22. An agent according to claim 20, wherein the agent is an antibody or a derivative thereof.

23. An agent according to claim 20, wherein the agent is used as a probe.

24. An agent according to claim 20, wherein the agent is labeled or labelable.

25. An agent according to claim 24, wherein the label is used in a technique selected from the group consisting of fluorescence, phosphorescence, chemiluminescence, radiation, enzyme-substrate reaction, and antigen-antibody reaction.

39. A vector according to claim 18, further comprising a sequence encoding a selectable marker.

19. A polypeptide, comprising:

(a) a polypeptide consisting of an amino acid sequence of positions 157 to 218 (homeodomain), positions 261 to 301 (W-rich region), or positions 399 to 455 (B2 repeat sequence region) set forth in SEQ ID NO. 4 or an amino acid sequence in corresponding positions, or a fragment thereof;

(b) a polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion, and wherein the variant polypeptide has biological activity;

(c) a polypeptide having at least 70% identity to anyone of the polypeptides of (a) to (b) and having biological activity.

37. A nucleic acid molecule, comprising a sequence of a promoter portion of a Stm gene.

38. A vector, comprising a nucleic acid molecule according to claim 37.

40. A cell, comprising a nucleic acid molecule according to claim 37.

41. An animal tissue, comprising a nucleic acid molecule according to claim 37.

42. An animal, comprising a nucleic acid molecule according to claim 37.

43. A composition, comprising a concentrated cell comprising a nucleic acid molecule according to claim 37.

44. A composition for determining an undifferentiated state of a cell, comprising an agent capable of reacting specifically with a Stm gene or a Stm gene product.

45. A composition according to claim 44, wherein the Stm gene or Stm gene product is:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity, or

(B) a polypeptide comprising;

(a) a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(b) a polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion, and wherein the variant polypeptide has biological activity;

(c) a polypeptide encoded by a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29;

(d) a polypeptide being a species homolog of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30;

or

(e) a polypeptide having at least 70% identity to anyone of the polypeptides of (a) to (d) and having biological activity.

46. A composition according to claim 44, wherein the cell is a stem cell.

47. A composition according to claim 44, wherein the cell includes an embryonic stem cell, a pluripotent stem cell, a unipotent stem cell, and a tissue stem cell.

48. A composition according to claim 44, wherein the cell includes a tissue stem cell selected from the group consisting of a neural stem cell, a gonadal stem cell, a hematopoietic stem cell, an epidermic stem cell, and mesenchymal tissue stem cell.

49. A composition according to claim 44, wherein the cell is genetically modified or is not genetically modified.

50. A method for determining an undifferentiated state of a cell, comprising the steps of:

(I) providing a cell to be determined;

(II) contacting an agent capable of reacting specifically with a Stm gene or a Stm gene product with the cell; and

(III) detecting a specific reaction between the agent and the Stm gene or the Stm gene product to determine whether or not the Stm gene is expressed in the cell,

wherein expression of the Stm gene in the cell indicates that the cell is in an undifferentiated state.

51. A method according to claim 50, wherein the undifferentiated state is totipotency.

52. A method according to claim 50, wherein the Stm gene or the Stm gene product comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity, or

(B) a polypeptide comprising;

(a) a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(b) a polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion, and wherein the variant polypeptide has biological activity;

(c) a polypeptide encoded by a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29;

(d) a polypeptide being a species homolog of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30;

or

(e) a polypeptide having at least 70% identity to anyone of the polypeptides of (a) to (d) and having biological activity.

53. A method according to claim 50, further comprising determining whether or not another stem cell marker is expressed.

54. A method according to claim 53, wherein the other stem cell marker includes Oct3/4.

55. A method according to claim 50, wherein the Stm gene is a Stm1 gene.

56. A method according to claim 55, wherein the Stm1 gene comprises a sequence set forth in SEQ ID NO. 1, 3, 5 or 29.

57. A method for preparing a cell in an undifferentiated state, comprising the steps of:

(I) providing a sample known or suspected of containing the cell in an undifferentiated state;

(II) contacting an agent capable of reacting specifically with a Stm gene or a Stm gene product with the sample;

(III) determining whether or not the Stm gene is expressed in the cell in the sample; and

(IV) isolating or concentrating the cell in which the Stm gene is expressed.

58. A method according to claim 57, wherein the undifferentiated state is totipotency.

59. A method according to claim 57, wherein the Stm gene or Stm gene product comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity, or

(B) a polypeptide comprising;

(a) a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(b) a polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion, and wherein the variant polypeptide has biological activity;

(c) a polypeptide encoded by a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29;

(d) a polypeptide being a species homolog of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30;

or

(e) a polypeptide having at least 70% identity to anyone of the polypeptides of (a) to (d) and having biological activity.

60. A method for preparing a cell in an undifferentiated state, comprising the steps of:

(I) providing the cell; and

(II) inducing expression of a Stm gene in the cell.

61. A method according to claim 60, wherein the undifferentiated state is totipotency.

62. A method according to claim 60, wherein the Stm gene comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity.

63. A method for isolating and/or growing and/or concentrating a cell in an undifferentiated state, comprising the steps of:

(I) providing a cell;

(II) introducing a Stm gene or a Stm gene promoter into the cell; and

(III) selecting the cell in which the Stm gene or the Stm gene promoter is expressed.

64. A method according to claim 63, wherein the undifferentiated state is totipotency.

65. A method according to claim 63, wherein the Stm gene or the Stm gene promoter comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity, or

(B) a sequence comprising a promoter portion of a Stm1 gene.

66. A kit for determining a differentiated state of a cell, comprising:

(a) an agent capable of reacting specifically with a Stm gene or a Stm gene product; and

(b) means for determining whether or not the Stm gene is expressed in the cell.

67. A kit according to claim 66, wherein the differentiated state is pluripotency.

68. A kit according to claim 66, wherein the differentiated state is totipotency.

69. A kit according to claim 66, wherein the Stm gene or Stm gene product comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity, or

(B) a polypeptide comprising;

(a) a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(b) a polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion, and wherein the variant polypeptide has biological activity;

(c) a polypeptide encoded by a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29;

(d) a polypeptide being a species homolog of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30;

or

(e) a polypeptide having at least 70% identity to anyone of the polypeptides of (a) to (d) and having biological activity.

70. A kit according to claim 66, further comprising means for determining whether or not another stem cell marker is expressed.

71. A kit according to claim 70, wherein the other stem cell marker includes Oct3/4.

72. A kit according to claim 66, wherein the Stm gene is a Stm1 gene.

73. A kit for preparing a cell in an undifferentiated state, comprising:

(I) an agent capable of reacting specifically with a Stm gene or a Stm gene product; and

(II) means for determining whether or not the Stm gene is expressed in the cell.

(III) isolating or concentrating the cell in which the Stm gene is expressed.

74. A kit according to claim 73, wherein the undifferentiated state is totipotency.

75. A kit according to claim 73, wherein the Stm gene or Stm gene product comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity, or

(B) a polypeptide comprising;

(a) a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(b) a polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion, and wherein the variant polypeptide has biological activity;

(c) a polypeptide encoded by a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29;

(d) a polypeptide being a species homolog of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30;

or

(e) a polypeptide having at least 70% identity to any one of the polypeptides of (a) to (d) and having biological activity.

76. A kit for preparing a cell in an undifferentiated state, comprising:

(I) means for inducing expression of a Stm gene in the cell.

77. A kit according to claim 76, wherein the undifferentiated state is totipotency.

78. A kit according to claim 76, wherein the Stm gene comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity.

79. A kit for preparing a cell in an undifferentiated state, comprising:

(I) a vector containing a Stm gene operably linked to a control sequence.

80. A kit according to claim 79, wherein the undifferentiated state is totipotency.

81. A kit according to claim 79, wherein the Stm gene comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity.

82. A kit for isolating and/or growing and/or concentrating a cell in an undifferentiated state, comprising:

(I) a Stm gene or a Stm gene promoter;

(II) means for introducing the Stm gene or the Stm gene promoter into the cell; and

(III) means for selecting the cell in which the Stm gene or the Stm gene promoter is expressed.

83. A kit according to claim 82, wherein the undifferentiated state is totipotency.

84. A kit according to claim 82, wherein the Stm gene comprises:

(A) a nucleic acid molecule comprising;

(a) a polynucleotide having a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(b) a polynucleotide encoding a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(c) a polynucleotide encoding a variant polypeptide having an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof, wherein at least one amino acid in the sequence has a mutation selected from the group consisting of substitution, addition, and deletion and wherein the variant polypeptide has biological activity;

(d) a polynucleotide, which is a spliced mutant or alleic mutant of a base sequence set forth in SEQ ID NO. 1, 3, 5 or 29, or a fragment thereof;

(e) a polynucleotide encoding a species homolog of a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO. 2, 4, 6 or 30, or a fragment thereof;

(f) a polynucleotide hybridizable to any one of the polynucleotides of (a) to (e) under stringent conditions and encoding a polypeptide having biological activity;

or

(g) a polynucleotide consisting of a base sequence having at least 70% identity to any one of the polynucleotides (a) to (e) or a complementary sequence thereof, and encoding a polypeptide having biological activity, or

(B) a sequence of a promoter portion of the Stm gene.