B6.Cg-Thy1^a/Cy Tg(TcraTcrb)8Rest/J

Stock number: 005023
Product name: pmel-1
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

This transgenic strain carries a rearranged T cell receptor transgene specific for the mouse homologue (pmel^Si or pmel-17) of human premelanosome protein (referred to as PMEL, SILV or gp100), and the T lymphocyte specific Thy1^a (Thy1.1) allele. About 1/3 of transgenic mice develop lymphomas by 5 to 7 months of age. These transgenic mice provide a tumor model system for studies related to immunotherapy, and for studying in vivo T-cell biology

Detailed description

This transgenic strain carries a rearranged T cell receptor transgene specific for the mouse homologue (pmel-17) of human SILV (gp100), an enzyme involved in pigment synthesis that is expressed by the majority of malignant melanoma cells including B16 melanoma, as well as by normal melanocytes. In mice from founder line 8 the transgenic integration was determined to be on Chromosome 2, in the 3' UTR of the serine threonine kinase 39 (Stk39) gene. STK39 is involved in the cellular stress response pathway. The strain is also homozygous for the T lymphocyte specific Thy1^a (Thy1.1) allele. CD8+ T cells express a Tcra-V1/Tcrb-V13- transgenic TCR that recognizes an epitope of pmel-17 corresponding to amino acids 25-33 of gp100 presented by H2-D^b MHC class I molecules. Greater than 95% of the CD8+ T cells in transgenic mice expressed the transgenic TCR based on the expression of Vbeta13, amounting to about 20% of all splenocytes. T cells in blood and spleen generally expressed baseline levels of the activation/effector markers CD25, CD44, and CD69, indicating that most of the transgenic cells were in the naive state.

In The Jackson Laboratory Repository colony, approximately 30% of transgenic mice develop lymphomas, found predominantly in the thymus and lymph nodes, at 5 to 7 months of age. Low incidence of earlier onset (by ~4 months) may be observed. Also around 5 months of age (or younger), ~half of transgenic mice may exhibit varying degrees of depigmentation (light salt and pepper to nearly white). Coat color lightening may be more prevalent in the males. Expression of Thy1.1 was confirmed in 2022 using flow cytometry and the OX7 monoclonal antibody.

These transgenic mice in conjunction with the poorly immunogenic B16 melanoma, a highly aggressive tumor in C57BL/6 mice, provide a physiologically relevant tumor model system for studies related to immunotherapy. In addition, these transgenic mice are useful for studying in vivo T-cell biology such as TCR-ligand interactions, T-cell activation, thymic selection, cross-presentation of antigens, process of thymic selection and central and peripheral T-cell tolerance and induction.

Development

Transgenic constructs containing rearranged alpha-chain and beta-chain of the T-cell receptor specific for the mouse homologue (pmel-17) of human SILV (gp100) were co-injected into fertilized C57BL/6 mouse eggs. Transgenic integration was on Chromosome 2, in the 3' UTR of the serine threonine kinase 39 (Stk39) gene. Mice from founder line 8 were bred to C57BL/6 mice, and then crossed with B6.PL-Thy1^a/CyJ (Stock No. 000406) mice.

In 2021, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While the 43 markers throughout the genome suggest a C57BL/6 genetic background, one of 5 markers that determine different C57BL/6 substrains were found to be segregating. This may be due to contributions from the PL/J regions in B6.PL-Thy1^a/CyJ.

Allele

Symbol: Tg(TcraTcrb)8Rest
Name: transgene insertion 8, Nicholas Restifo
MGI accession ID: MGI:3051150
Generation method: Transgenic
Attributes: Inserted expressed sequence
Marker symbol: Tg(TcraTcrb)8Rest
Marker name: transgene insertion 8, Nicholas Restifo
Chromosome: 2
Strain of origin: C57BL/6
Expressed genes: Tcra,T cell receptor alpha chain,mouse, laboratory; Tcrb,T cell receptor beta chain,mouse, laboratory
Molecular note: These coinjected transgenes encode an H2-D^b-restricted Valpha1 Vbeta13 T-cell receptor that recognizes a peptide comprising amino acids 25-33 of the protein known as pmel-17/gp100, a pigment biosynthetic enzyme that is encoded by the mouse Si (silver) gene and is expressed both in normal melanocytes and in malignant melanoma. The insertion is accompanied by a 157-bp deletion (chr2: 68,208,872?68,209,029 bp - build unknown).

Allele

Symbol: Thy1^a
Name: a variant
MGI accession ID: MGI:3579311
Generation method: Not Applicable
Marker symbol: Thy1
Marker name: thymus cell antigen 1, theta
Chromosome: 9
Strain of origin: Not Applicable
Site of expression: The Thy1 locus determines a surface antigen present on cells of the thymus, a number of mouse leukemias, brain, and in lesser amounts on lymph node and spleen cells.
Molecular note: The allele Thy1^a determines an antigenic specificity, Thy-1.1, found in the AKR and RF strains.
General note:

The Thy1 locus determines a surface antigen present on cells of the thymus, a number of mouse leukemias, brain, and in lesser amounts on lymph node and spleen cells. The allele Thy1^a determines an antigenic specificity, Thy-1.1, found in the AKR and RF strains; the allele Thy1^b determines an antigenic specificity, Thy-1.2, found in the C3HeB/Fe and many other strains (J:5243, J:5012, J:4469). The Thy1 antigen is probably present on all T lymphocytes and absent from all B lymphocytes, and it thus serves as a valuable T-cell marker (J:5243). It is very widely used in experiments designed to determine the distribution and function of T-cells. Thy1 specifies a T-cell surface glycoprotein, T25, with a molecular weight of 25 kDa (J:5707). The protein appears to be anchored in the cell membrane by a lipid that is either phosphotidylinositol or closely related to it (J:12016). Thy1 may function in the cell membrane as a signal transduction molecule (J:8333). The Thy1 locus, or possibly a gene closely linked to it, controls quantitative expression of a protein that is the same size as Thy1 and is expressed on thymus and brain but not on lymph node and spleen cells (J:7900).