Mice are provided that comprise a reduction or deletion of ADAM6 activity from an endogenous ADAM6 locus, or that lack an endogenous locus encoding a mouse ADAM6 protein, wherein the mice comprise a sequence encoding an ADAM6 or ortholog or homolog or fragment thereof that is functional in a male mouse. In one embodiment, the sequence is an ectopic ADAM6 sequence or a sequence that confers upon a male mouse the ability to generate offspring by mating. Mice and cells with genetically modified immunoglobulin heavy chain loci that comprise an ectopic nucleotide sequence encoding a mouse ADAM6 or functional fragment or homolog or ortholog thereof are also provided.

The present invention contemplates isolated polynucleotide for the production of a VHH-containing heavy chain antibody in a mammal and vectors comprising said isolated polynucleotide. Moreover, the invention relates to a transgenic mammal comprising the vector for the production of a VHH-containing heavy chain antibody. Further, the invention relates to VHH-containing heavy chain antibodies as well as methods for the production and cloning of VHH-containing heavy chain antibodies.

The invention relates to bacterial artificial chromosomes (BAC) comprising retroviral nucleic acid sequences encoding: gag and pol proteins, and an env protein or a functional substitute thereof, wherein each of the retroviral nucleic acid sequences are arranged as individual expression constructs within the BAC. The invention also relates to uses and methods of transient transfection using said BAC.

Non-human animals, tissues, cells, and genetic material are provided that comprise a modification of an endogenous non-human heavy chain immunoglobulin sequence and that comprise an ADAM6 activity functional in a mouse, wherein the non-human animals express a human immunoglobulin heavy chain variable domain and a cognate human immunoglobulin light chain variable domain.

A genetically modified mouse is provided, wherein the mouse expresses an immunoglobulin light chain repertoire characterized by a limited number of light chain variable domains. Mice are provided that present a choice of two human light chain variable gene segments such that the immunoglobulin light chains expresses by the mouse comprise one of the two human light chain variable gene segments. Methods for making bispecific antibodies having universal light chains using mice as described herein, including human light chain variable regions, are provided. Methods for making human variable regions suitable for use in multispecific binding proteins, e.g., bispecific antibodies, and host cells are provided.

The present invention is related to a nucleic acid molecule, which is also referred to as third nucleic acid molecule, wherein the third nucleic acid molecule comprises (1) a nucleic acid molecule comprising the following elements: (a) optionally, a first part of a genome of a virus; (b) a nucleotide sequence, preferably a genomic nucleotide sequence, or a transcription unit; (c) a regulatory nucleic acid sequence which has a regulatory activity in a prokaryote; (d) exactly one site-specific recombination site; (e) a nucleotide sequence providing for a negative selection marker; (f) a bacterial nucleotide sequence unit comprising (i) bacterial nucleotide sequences for conditional replication and (ii) a nucleotide sequence providing for a positive selection marker; (g) optionally a first restriction site; or (2) a nucleic acid molecule comprising a nucleotide sequence according to SEQ ID NO: 6; or (3) a nucleic acid molecule identical or similar to the nucleic acid molecule contained in the organism deposited with the DSMZ under the Budapest treaty under accession number DSM 23754, wherein preferably the nucleic acid molecule contained in the organism is a heterologous nucleic acid molecule; wherein the third nucleic acid molecule is either a linear or a circular molecule.

A method for engineering and utilizing large DNA vectors to target, via homologous recombination, and modify, in any desirable fashion, endogenous genes and chromosomal loci in eukaryotic cells. These large DNA targeting vectors for eukaryotic cells, termed LTVECs, are derived from fragments of cloned genomic DNA larger than those typically used by other approaches intended to perform homologous targeting in eukaryotic cells. Also provided is a rapid and convenient method of detecting eukaryotic cells in which the LTVEC has correctly targeted and modified the desired endogenous gene(s) or chromosomal locus (loci) as well as the use of these cells to generate organisms bearing the genetic modification.

Provided here are compositions for a bacterial artificial chromosome-based construct containing a replication-competent recombinant severe acute respiratory syndrome coronavirus-2 genome and methods of making such compositions and uses thereof.

Some embodiments relate to a method for producing a product of interest with a microbial host using an auto-replicative extra-chromosomal nucleic acid molecule comprising a first nucleic acid sequence whose genetic activity confers an advantage to the host, optionally wherein the genetic activity of said first nucleic acid molecule is controlled.

Mice are provided that comprise a reduction or deletion of ADAM6 activity from an endogenous ADAM6 locus, or that lack an endogenous locus encoding a mouse ADAM6 protein, wherein the mice comprise a sequence encoding an ADAM6 or ortholog or homolog or fragment thereof that is functional in a male mouse. In one embodiment, the sequence is an ectopic ADAM6 sequence or a sequence that confers upon a male mouse the ability to generate offspring by mating. Mice and cells with genetically modified immunoglobulin heavy chain loci that comprise an ectopic nucleotide sequence encoding a mouse ADAM6 or functional fragment or homolog or ortholog thereof are also provided.