These double knock-out mice exhibit reductions in leukocyte rolling and in extravasation of neutrophils in thioglycollate-induced peritonitis.
Dr. Richard Hynes, Massachusetts Institute of Technology
Genetic Background | Generation |
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Allele Type | Gene Symbol | Gene Name |
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Targeted (Null/Knockout) | Selp | selectin, platelet |
Allele Type | Gene Symbol | Gene Name |
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Targeted (Null/Knockout) | Sell | selectin, lymphocyte |
Mice that are homozygous null for the Sell and Selp genes are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. No Sell and Selp gene products (mRNA or protein) are detected. Leukocytes from these mice exhibit a deficiency in the ability to interact with, and roll along, the venular wall endothelium. Such a deficiency in the crucial first step of leukocyte recruitment to surrounding tissues in response to infection or injury results in elevated leukocyte counts in the peripheral blood. These defects are largely due to absence of Selp. In addition, lack of Sell leads to failure of lymphocytes to enter lymph nodes and gthus to hypoplastic lymph nodes. These mice are suitable for use in research applications studying leukocyte homing, infectious diseases and inflammation.
Sequential mutation by homologous recombination was utilized to replace the Sell and Selp genes with drug-resistance genes for neomycin and puromycin (respectively) in 129S2/SvPas derived D3 embryonic stem (ES) cells. This approach was necessary because the Sell and Selp genes are too closely linked for double-deficient animals to be generated by mating single-deficient animals. Correctly targeted ES cells were injected into C57BL/6 blastocysts and chimeric offspring obtained.
Allele Name | targeted mutation 1, Richard Hynes |
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Allele Type | Targeted (Null/Knockout) |
Allele Synonym(s) | P-; P-selectin-; P-Selp- |
Gene Symbol and Name | Selp, selectin, platelet |
Gene Synonym(s) | |
Strain of Origin | 129S2/SvPas |
Chromosome | 1 |
Molecular Note | A portion of exon 3 encoding 10 amino acids of a signal peptide and 27 amino acids of the lectin domain was replaced with a PGK-neo cassette. Mice were treated with lipopolysaccharide to augment the normally low levels of selectin in lung and liver tissue. A longer transcript, resulting from aberrant or cryptic splicing involving the neomycin cassette, was detected at low levels in mutant mice by Northern blot analysis. RT-PCR further confirmed the presence of low levels of transcript in homozygous mice. Immunofluorescence analysis of activated platelets and lung sections from homozygous mutant mice showed an absence of encoded protein. These results were further confirmed by flow cytometric analysis of activated platelets and metabolic labeling of lung tissue. |
Mutations Made By | Dr. Richard Hynes, Massachusetts Institute of Technology |
Allele Name | targeted mutation 3, Richard Hynes |
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Allele Type | Targeted (Null/Knockout) |
Allele Synonym(s) | L-selectin- |
Gene Symbol and Name | Sell, selectin, lymphocyte |
Gene Synonym(s) | |
Strain of Origin | 129S2/SvPas |
Chromosome | 1 |
Molecular Note | The three selectin genes, Sele, Sell, and Selp, are found within a 300 kb genomic region. To generate double knockouts, ES cells heterozygote for the Selptm1Hyn and Seletm2Hyn null alleles in trans to each other were targeted a third time. A PGK-puro cassette was used to delete a 2.1 kb region containing the exons encoding the lectin domain and most of the epidermal growth factor domain. Flow cytometric analysis of homozygote leukocytes showed an absence of the L-selectin and P-selectin protein while E-selectin expression was unaffected. Thus, this targeted mutation occurred in cis with the Selptm1Hyn allele and in trans with the Seletm2Hyn allele. Due to their genomic proximity, the Selltm3Hyn and Selptm1Hyn alleles should propagate together through the offspring. |
This strain originated on a B6:129S2 background and is maintained as a homozygote. The donating lab maintained these mice by avoiding brother-sister matings.
When using the PL- mouse strain in a publication, please cite the originating article(s) and include JAX stock #003805 in your Materials and Methods section.
Facility Barrier Level Descriptions
Service/Product | Description | Price |
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Homozygous for Selp<tm1Hyn>, Homozygous for Sell<tm1Hyn>, 1 pair minimum |
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The Jackson Laboratory has rigorous genetic quality control and mutant gene genotyping programs to ensure the genetic background of JAX® Mice strains as well as the genotypes of strains with identified molecular mutations. JAX® Mice strains are only made available to researchers after meeting our standards. However, the phenotype of each strain may not be fully characterized and/or captured in the strain data sheets. Therefore, we cannot guarantee a strain's phenotype will meet all expectations. To ensure that JAX® Mice will meet the needs of individual research projects or when requesting a strain that is new to your research, we suggest ordering and performing tests on a small number of mice to determine suitability for your particular project. We do not guarantee breeding performance and therefore suggest that investigators order more than one breeding pair to avoid delays in their research.
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