Disclosed herein are chimeric mammals, such as a chimeric mammal comprising cells derived from at least a first mammal and a second mammal, wherein the cells from the first mammal comprise a genetic modification at one or more loci and the cells from the second mammal form at least one organ or tissue, wherein the first and second mammals are different species.

A method for establishing an animal model of hepatocellular carcinoma (HCC) bone metastasis, the method including: 1) establishing 97H and LM3 cell clones with stable expression of firefly luciferase (LUC); 2) allowing HCC cells to form bone metastasis in nude mice via intratibial injection; 3) reproducing HCC bone metastasis in nude mice via intracardiac injection of tumor cells; and 4) isolating a sub-population of tumor cells that targets metastasis to bone. The 97H and the LM3 are highly metastatic HCC cell lines transfected with luciferase gene. BALB/cA-nu mice are 4-5 weeks old and maintained in laminar flow cabinets under SPF conditions and received human care throughout an entire study. A cell number for intratibial injection is 0.5×10.sup.6, and a cell number for intracardiac injection is 1×10.sup.6.

The present disclosure relates to the genetically modified non-human animals that express a human or chimeric (e.g., humanized) T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), and methods of use thereof.

The present invention provides an immuno-deficient animal useful as an animal model for a human disease associated with a first mutation of a target gene, wherein the animal comprises (a) a first human xenograft comprising the target gene comprising the first mutation; (b) a second human xenograft comprising the target gene but lacking the first mutation, wherein the first human xenograft and second human xenograft are isogenic. Also provided here are methods of producing the animal model and methods of using such animal model.

The present disclosure provides methods and compositions for enhanced editing of genomic DNA. For example, in some embodiments, a subject method is a method of editing genomic DNA of a eukaryotic cell and the method includes introducing into a eukaryotic cell a composition comprising: (a) a linearized non-homologous DNA composition and (b) a genome targeting composition (which includes a genome editing endonuclease, or a nucleic acid encoding the genome editing endonuclease). In some cases in which the genome editing endonuclease is a CRISPR/Cas endonuclease, the genome targeting composition can also include a corresponding CRISPR/Cas guide RNA.

The invention provides compositions and methods useful for the treatment and prevention of conditions associated with short telomere length.

Methods of generating modified embryos and mammals by introduction of donor cells into an early stage embryo are provided, such that the resulting embryo and animal generated therefrom has a significant contribution to all tissues from the donor cells and is capable of transmitting the donor cell DNA.

Non-human animals, cells, methods and compositions for making and using the same are provided, wherein the non-human animals and cells comprise a humanized a proliferation-inducing ligand gene. Non-human animals and cells that express a human or humanized a proliferation-inducing ligand protein from an endogenous a proliferation-inducing ligand locus are described.

The present invention is transgenic chickens obtained from long-term cultures of avian PGCs and techniques to produce and transgenic birds derived from prolonged PGC cultures. In some embodiments, these PGCs can be transfected with genetic constructs to modify the DNA of the PGC, specifically to introduce a transgene encoding an exogenous protein. When combined with a host avian embryo by known procedures, those modified PGCs are transmitted through the germline to yield transgenic offspring. This invention includes compositions comprising long-term cultures of PGCs and offspring derived from them that are genetically modified. The genetic modifications introduced into PGCs to achieve the gene inactivation may also include, but are not restricted to, random integrations of transgenes into the genome, transgenes inserted into the promoter region of genes, transgenes inserted into repetitive elements in the genome, site specific changes to the genome that are introduced using integrase, site specific changes to the genome introduced by homologous recombination, and conditional mutations introduced into the genome by excising DNA that is flanked by lox sites or other sequences that are substrates for site specific recombination.

The invention provides methods and compositions for perturbing gene expression in hematopoietic cell lineages in vivo.