Important Note
Important Note regarding transgene insertion and linkage to H-2b MHC haplotype: In Liu et al. 2020 J Immunol. 204:1982 [PMID:32122998], it was discovered that the UBC-GFP transgene integrated into chromosome 17 at nucleotide position 29,435,589 (reference sequence NC_000083.6; GRCm38.p6) - this is a noncoding region centromeric from the H-2 locus (~4.6 Mbp away from H2-K1). The number of transgene copies was not determined. Furthermore, this determined that BALB/cBy-congenic UBC-GFP transgenic mice (N11+ from Stock No. 007076) retained the H-2b MHC haplotype from the genetic background upon which it was created (C57BL/6), rather than the H-2d MHC haplotype of BALB/cBy.
As of June 2020, all live breeder mice in the Stock No. 007076 colony genotyped as homozygous for H-2b and negative for H-2d.
In July-August 2020, a cohort of homozygous mice were confirmed to have H-2 Db and H-2 Kb expression in peripheral blood, similar to C57BL/6 [view data; July-August 2020].
Although the UBC-GFP transgene inserted close to the H-2 locus, segregation is possible. For experiments where MHC haplotype is a factor, researchers should determine if the UBC-GFP transgenic mice are H-2b or H-2d.
Detailed Description
In 2020, the UBC-GFP transgene was determined to have integrated at Chr17:29,435,589 - a noncoding region centromeric from the H-2 locus (~4.6 Mbp away from H2-K1) - and is closely linked to H-2b MHC haplotype. See Important Note for additional details.
These UBC-GFP transgenic mice express Enhanced Green Fluorescent Protein (EGFP) under the direction of the human ubiqutin C promoter.
Mice hemizygous for the transgene are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. These mice express EGFP in all tissues examined. Certain hematopoietic cell types display distinct expression levels of EGFP, allowing identification of different cells types by FACS analysis. EGFP expression is uniform within a cell type lineage and remains constant throughout development. T cells have a 2-fold higher EGFP expression than CD19+B220+ B cells or peripheral blood cells. Leukocytes and red blood cells from homozygous mice fluoresce at approximately twice the level of cells from hemizygous mice. This mutant mouse strain represents a useful tool in studies related to hematopoietic cell differentiation and in vivo tracking of leukocytes.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This is the case for the strain above. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
