Transgenic ungulates having reduced prion protein activity and uses thereof

• US 20090165154A1
• Filed: 09/05/2008
• Published: 06/25/2009
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: SAB LLC (W.P. Carey, Inc. (Real Estate))
• Original Assignee: BioDak LLC
• Inventors: Ishida, Isao, Kuroiwa, Yoshimi, Tomizuka, Kazuma, Robl, James M.
• Granted Patent: US 7,807,863 B2
• Time in Patent Office: Days
• US Class Current: 800/15
• CPC Class Codes: A01K 2207/15 Humanized animals
• CPC Class Codes: A01K 2217/00 Genetically modified animals
• CPC Class Codes: A01K 2217/05 Animals comprising random inserted nucleic acids (transgenic)
• CPC Class Codes: A01K 2217/072 maintaining or altering function, i.e. knock in
• CPC Class Codes: A01K 2227/101 Bovine
• CPC Class Codes: A01K 2267/01 Animal expressing industrially exogenous proteins
• CPC Class Codes: A01K 2267/02 Animal zootechnically ameliorated
• CPC Class Codes: A01K 67/0271 Chimeric vertebrates, e.g. comprising exogenous cells
• CPC Class Codes: A01K 67/0276 Knock-out vertebrates
• CPC Class Codes: A01K 67/0278 Knock-in vertebrates, e.g. humanised vertebrates
• CPC Class Codes: C07K 16/00 Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies antibodies with enzymatic activity, e.g. abzymes C12N9/0002
• CPC Class Codes: C07K 2317/12 isolated from milk
• CPC Class Codes: C07K 2317/21 from primates, e.g. man
• CPC Class Codes: C12N 15/8509 for producing genetically modified animals, e.g. transgenic
• CPC Class Codes: C12N 2800/30 Vector systems comprising sequences for excision in presence of a recombinase, e.g. loxP or FRT

Abstract

The invention provides cloned transgenic ungulates (e.g., bovines) in which prion protein activity is reduced by one or more genetically engineered mutations. Desirably, these transgenic bovines are also genetically modified to express xenogenous (e.g., human) antibodies. Because of their resistance to prion-related diseases such as bovine spongiform encephalopy (also known as mad cow disease), these bovines are a safer source of human antibodies for pharmaceutical uses and a safer source of agricultural products.

Claims

1. A bovine whose genome comprises a non-naturally occurring mutation in one or both alleles of an endogenous prion nucleic acid, wherein said bovine exhibits reduced functional prion production.

2. The bovine of claim 1, wherein said mutation substantially eliminates the expression of functional prion protein.

3. The bovine of claim 1, wherein said mutation is hemizygous.

4. The bovine of claim 1, wherein said mutation is homozygous and said bovine exhibits no functional prion production.

5. The bovine of claim 1, wherein said mutation comprises an insertion of a positive selection marker into a prion nucleic acid.

6. The bovine of claim 1, wherein said mutation comprises an insertion of a transcriptional termination sequence or STOP codon, or both, into a prion nucleic acid.

7. The bovine of claim 1, wherein said mutation comprises a deletion of one or more nucleotides in a prion nucleic acid.

8. An isolated bovine cell comprising a non-naturally occurring mutation in one or both alleles of an endogenous prion nucleic acid, wherein said bovine cell exhibits reduced functional prion production.

9. The cell of claim 8, wherein said mutation is hemizygous.

10. The cell of claim 8, wherein said mutation is homozygous and said bovine cell exhibits no functional prion production.

11. The cell of claim 8, wherein said cell is a fetal fibroblast.

12. The cell of claim 8, wherein said cell is a B-cell.

13. A method for producing an isolated transgenic bovine cell having reduced expression of functional prion protein, comprising

(a) introducing a first prion gene targeting vector into a bovine cell under conditions that allow homologous recombination between said first vector and a first allele of an endogenous prion nucleic acid in said cell, thereby introducing a hemizygous mutation in said cell;

(b) isolating said bovine cell containing hemizygous mutation; and

(c) introducing a second prion gene targeting vector having a different selectable marker than said first vector into said bovine cell of step (b) under conditions that allow homologous recombination between said second vector and a second allele of an endogenous prion nucleic acid in said cell, thereby introducing a homozygous mutation in said bovine cell.

14. The method of claim 13, wherein said cell is a bovine fibroblast.

15. The method of claim 13, wherein said cell is a bovine fetal fibroblast.

16. A method for producing a transgenic bovine having reduced expression of functional prion protein, said method comprising the steps of:

(a) inserting a diploid permeabilized cell into an enucleated metaphase II oocyte, wherein said cell comprises a first non-naturally occurring mutation in an endogenous prion nucleic acid; and

(b) transferring said oocyte or an embryo formed from said oocyte into the uterus of a host bovine under conditions that allow said oocyte or said embryo to develop into a fetus, wherein the genome of said fetus comprises said non-naturally occurring mutation in said endogenous prion nucleic acid and wherein said fetus exhibits reduced functional prion production.

17. The method of claim 16, wherein said fetus develops into a viable offspring.