In this strain a NEO cassette replaces exon 1 of the Plcb3, phospholipase C, beta 3, gene. These mice exhibit increased sensitivity to morphine and altered calcium ion release response and have applications in studies of allergic reactions, opioid response and nociception.
Melvin Simon, University of California, San Diego
Phospholipase C, beta 3, is critical to G protein-coupled receptor signal transduction pathways regulating mast cell activation and cell migration, as well as intracellular calcium ion release. These mice carry a targeted mutation in which a NEO selection cassette replaced exon 1, encoding the X box of the catalytic domain. Mice that are homozygous for the targeted mutation are viable and fertile. No gene product (mRNA or protein) is detected by Western blot analysis of dorsal root ganglion neurons and neutrophils. Homozygotes exhibit a 5-fold increased sensitivity to morphine, and increased sensitivity to a mu opioid agonist. In reponse to somatostatin, there is no influx of calcium into in aortic smooth muscle cells of homozygotes. Homozygotes 6 months or older sometimes develop skin ulcers around the head area, with infiltration of leukocytes in to the lesions. Histamine, selective H1 histamine receptor agonist, and mast cell activator challenges do not elicit scratching behavior in null mice. Dorsal root ganglion neurons isolated from homozygotes exhibit a decreased calcium response to histamine. Complement 5a induced calcium ion efflux in peritoneal macrophages from homozygotes is decreased when compared to the response in control animals. After thioglycollate treatment, homozygotes exhibit an increase in macrophage apoptosis, resulting in fewer peritoneal macrophages. Macrophages from null mice are hypersensitive to apoptosis inducers such as oxysterol and LPS/cycloheximide. Chemotactic response to antigen of IgE-sensitized bone marrow cells (isolated from homozygotes) is reduced. Bone marrow cells from homozygotes produce less IL-6, TNF-alpha, and IL-13, and exhibit increased Lyn kinase activity.
A targeting vector containing NEO cassette was used to disrupt part of the exon encoding the X box of the catalytic domain. The construct was electroporated into unspecified embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were crossed to C57BL/6 mice, and then backcrossed to C57BL/6 for 5 generations.
Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
|Allele Name||targeted mutation 1, Dianqing Wu|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||PLC beta3-null|
|Gene Symbol and Name||Plcb3, phospholipase C, beta 3|
|Strain of Origin||Not Specified|
|Molecular Note||A neomycin selection cassette replaced part of the exon encoding the X box. Western blot analysis demonstrated that no detectable protein was present in homogenates of dorsal root ganglia derived from homozygous mice.|
|Mutations Made By|| |
Estelle Wall, University of California, San Diego
When maintaining a live colony, these mice can be bred as homozygotes.
When using the B6.Cg-Plcb3tm1Dwu/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #019023 in your Materials and Methods section.