A genetically modified immunodeficient non-human animal whose genome includes a genetic modification that renders the non-human animal deficient in macrophages and/or macrophage anti-human red blood cell activity so as to prolong the survival of human red blood cells when administered into said non-human animal is provided according to aspects of the present invention. Methods of assaying effects of putative therapeutic agents in such a genetically modified immunodeficient non-human animal are provided by the present invention.

Described herein is an animal model useful for identifying therapeutic agents that can inhibit the physiological effects or symptoms of COVID-19 infection, including the effects of the following on one or more organs of the animal: inflammation, oxidative stress, fibrin deposition, blood brain barrier breakdown, clotting, and vascular problems.

Non-human animals comprising a human or humanized DPP4 nucleic acid sequence are provided. Non-human animals that comprise a replacement of the endogenous Dpp4 gene with a human or humanized DPP4 gene, or non-human animals comprising a human or humanized DPP4 gene in addition to the endogenous Dpp4 gene are described. Non-human animals comprising a human or humanized DPP4 gene under control of human or non-human DPP4 regulatory elements is also provided, including non-human animals that have a replacement of non-human Dpp4-encoding sequence with human DPP4-encoding sequence at an endogenous non-human Dpp4 locus. Non-human animals comprising human or humanized DPP4 gene sequences, wherein the non-human animals are rodents, e.g., mice or rats, are provided. Methods for making and using the non-human animals are described.

Disclosed herein are nucleic acids encoding for and proteins expressing chimeric C1q polypeptides, non-human animals comprising said nucleic acids, and methods of making or using said non-human animals.

Non-human animals comprising a human or humanized DPP4 nucleic acid sequence are provided. Non-human animals that comprise a replacement of the endogenous Dpp4 gene with a human or humanized DPP4 gene, or non-human animals comprising a human or humanized DPP4 gene in addition to the endogenous Dpp4 gene are described. Non-human animals comprising a human or humanized DPP4 gene under control of human or non-human DPP4 regulatory elements is also provided, including non-human animals that have a replacement of non-human Dpp4-encoding sequence with human DPP4-encoding sequence at an endogenous non-human Dpp4 locus. Non-human animals comprising human or humanized DPP4 gene sequences, wherein the non-human animals are rodents, e.g., mice or rats, are provided. Methods for making and using the non-human animals are described.

Generation of chimeric non-human animals hosting bat donor cells involves chimeric mice having bat cells that may be stably tolerated to provide a new platform technology in the general field of biology, and having application in the field of immunology related to virus-host interaction, cancer biology, autoimmunity, and the development of new drugs.

Provided are an animal preparation method and use thereof. The method includes aggregating a tetraploid embryo with embryonic stem cells to form a new reconstructed embryo or chimera embryo, the tetraploid embryo being a tetraploid embryo developed to 2-cell stage. By aggregating a 2-cell tetraploid embryo with embryonic stem cells, problems of poor efficiency and poor stability of mice preparation using the tetraploid complementation technique as well as low efficiency when embryonic stem cells from pure line mice are used are alleviated, the birth rate of mice is improved to a level close to that of normal embryo transplantation, and embryos and adult mice can be directly prepared from stem cells for phenotypic research.

Provided are a method and use of microRNA MiR-2911 in regulating an ebola virus. Particularly provided are a method and use of isolated microRNA MiR-2911 in regulating an ebola virus protein gene.

Genetically modified rodents such as mice and rats, and methods and compositions for making and using the same, are provided. The rodents comprise a humanization of at least one endogenous rodent Tmprss gene, such as an endogenous rodent Tmprss2, Tmprss4, or Tmprss11d gene.

The application provides, among others, methods for constructing animal obesity models, methods for screening microorganism or composition of microorganisms that may cause obesity, methods for screening therapeutic targets for treating metabolic disorders, and methods for screening or evaluating microorganisms, compounds, food, recipes, formulations, drugs, nutritional supplements, healthcare products, beverages and other items for preventing and treating metabolic diseases.