Germ-line transmission of a disrupted β2microglobulin gene produced by homologous recombination in embryonic stem cells

Abstract

Major histocompatibility complex (MHC) class I molecules are integral membrane proteins present on virtually all vertebrate cells and consist of a heterodimer between the highly polymorphic alpha-chain and the beta 2-microglobulin (beta 2-m) protein of relative molecular mass 12,000 (ref. 1). These cell-surface molecules play a pivotal part in the recognition of antigens, the cytotoxic response of T cells, and the induction of self tolerance. It is possible, however, that the function of MHC class I molecules is not restricted to the immune system, but extends to a wide variety of biological reactions including cell-cell interactions. For example, MHC class I molecules seem to be associated with various cell-surface proteins, including the receptors for insulin, epidermal growth factor, luteinizing hormone and the beta-adrenergic receptor. In mice, class I molecules are secreted in the urine and act as highly specific olfactory cues which influence mating preference. The beta 2-m protein has also been identified as the smaller component of the Fc receptor in neonatal intestinal cells, and it has been suggested that the protein induces collagenase in fibroblasts. Cells lacking beta 2-m are deficient in the expression of MHC class I molecules, indicating that the association with beta 2-m is crucial for the transport of MHC class I molecules to the cell surface. The most direct means of unravelling the many biological functions of beta 2-m is to create a mutant mouse with a defective beta 2-m gene. We have now used the technique of homologous recombination to disrupt the beta 2-m gene. We report here that introduction of a targeting vector into embryonic stem cells resulted in beta 2-m gene disruption with high frequency. Chimaeric mice derived from blastocysts injected with mutant embryonic stem cell clones transmit the mutant allele to their offspring.

A Putative 12 Transmembrane Domain Cotransporter Expressed in Thymic Cortical Epithelial Cells

“…Mice bearing the following gene-targeted mutations were derived into our breeding colony at Taconic Farms (Germantown, NY) by embryo transfer and backcrossed when necessary to C57BL/6 or C57BL/10 mice. The N number is the number of crosses at the time the mice were used: the recombinase activating gene 2 (RAG2) Ϫ/Ϫ (N11) (11), ␤ 2 -microglobulin Ϫ/Ϫ (N11) (12), invariant chain Ϫ/Ϫ (N10) (13), IFN-␥ Ϫ/Ϫ (GKO) (N7) (14), and TCR-␣ Ϫ/Ϫ (N12) (15).…”

Targeted disruption of the MHC class II Aa gene in C57BL/6 mice

“…The central role of MHC molecules in the development and function of lymphocytes has also been addressed in MHC class I and MHC class ll-deficient mice generated by targeted mutation (6)(7)(8)(9). In mice of H-2 b haplotype, a naturally occurring mutation in the Ea promoter region blocks the expression of Ea genes, and leads to the lack of EctEfi heterodimers on the surface of thymic epithelial cells, dendritic cells, macrophages, and B cells (10).…”

Prix Nobel de Médecine 2007

“…Avec la mise au point un an plus tard d'une stratégie de sélection baptisée sélection positive-négative, le groupe de Mario Capecchi démontrait que le ciblage, dans les cellules ES, de n'importe quel gène de souris était possible [14]. La publication des premières souris mutantes obtenues par recombinaison homologue dans les cellules ES a lieu en 1989 [15][16][17][18]. Cette méthodologie s'est ensuite propagée très rapidement dans la communauté des généticiens de la souris et l'on dénombre à ce jour plus de 12 000 lignées de souris (plus de 5 000 gènes ciblés) obtenues par mutagenèse dirigée.…”