Cultured LPS stimulated bone marrow derived macrophages from homozygous animals secrete less IL1 beta and IL1 alpha; IL18 is undetectable when compared with hemizygous and wild-type controls. Diabetes frequency of Casp1tm1Sesh deficient animals is equivalent to NOD/Lt, heterozygote and wild-type controls. This strain is a useful model for studying the role of IL1 and IL18 cytokines in inflammatory processes relating to diabetes.
Dr. Edward Leiter, The Jackson Laboratory
Casp1tm1Sesh homozygous mice are viable, fertile, normal in size, and do not display any gross physical or behavioral abnormalities. There is no detectable expression of Casp1 in spleen by northern blot analysis or by RT-PCR of peritoneal exudate cells, brain, lung, heart, liver, adrenal gland, kidney, testis, and thymus (Li et al, 1995). Cultured LPS stimulated bone marrow derived macrophages from homozygous NOD.129S2(B6)- Casp1tm1Sesh /LtJ animals secrete 4-fold less IL1 beta, 30% less IL1 alpha, and IL18 is undetectable when compared with hemizygous and wild-type controls. Diabetes frequency of Casp1tm1Sesh deficient animals is equivalent to NOD/Lt, heterozygote and wild-type controls. Weanling Casp1tm1Sesh homozygous animals injected with Complete Freund's adjuvant and young pre-diabetic males treated with multiple low dose streptozotocin behave similarly to control (wild type, heterozygote, or NOD/Lt) animals (Schott et al, 2004). NOD.129S2(B6)- Casp1tm1Sesh/LtJ is a useful model for studying the role of IL1 and IL18 cytokines in inflammatory processes relating to diabetes.
A construct containing a neomycin expression cassette inserted into exon 6 of Casp1 (cloned from a 129/Sv mouse), deleting 31 bp of sequence encoding the region of the catalytic active site and rendering the sequence out of frame after the insertion, was transfected into D3 (129S2/SvPas derived) embryonic stem cells (ES cells). These ES cells were injected into C57BL/6 blastocysts. Chimeric founders were initially mated to C57BL/6 and subsequently intercrossed to generate homozygotes (Li et al, 1995). In 1998, Dr. Edward Leiter at The Jackson Laboratory received B6.129S2-Casp1tm1Sesh mice from Dr. Winnie Wong, BASF Bioresearch Corporation and backcrossed this mutation to NOD/Lt for 10 generations, subsequently intercrossing to generate homozygotes (Schott et al. 2004). In 2004, NOD.129S2(B6)- Casp1tm1Sesh /LtJ homozygous strain at N10F11 was transferred from Edward Leiter's research colony to a Jackson Laboratory distribution colony.
|Allele Name||targeted mutation 1, Tara Seshadri|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Casp1 -; casp-1-; Casp1-/Casp11129mt; Caspase-1-; ICE -|
|Gene Symbol and Name||Casp1, caspase 1|
|Strain of Origin||129S2/SvPas|
|General Note||The ES cells used to generate this allele contain the linked Casp4del truncated allele that fails to produce a functional Casp4. Phenotypes associated with this allele may be affected by the presence of the Caspdel allele. J:193522|
|Molecular Note||A neomycin expression cassette was inserted into exon 6, deleting 31 bp of sequence encoding the region of the active site and rendering the sequence out of frame after the insertion. Northern blot analysis on spleen RNA demonstrated an absence of the normal transcript in homozygous mice, and western blot analysis showed that the protein was not expressed in peritoneal macrophages of homozygous mice. This allele was generated in ES cells that lack protein expression of Casp11 (Casp129mt).|
|Mutations Made By|| |
Dr. Edward Leiter, The Jackson Laboratory
|Allele Type||Spontaneous (Null/Knockout)|
|Gene Symbol and Name||Casp4, caspase 4, apoptosis-related cysteine peptidase|
|Strain of Origin||129P3/J and 129S1/SvImJ and 129S2/SvPas and 129S6/SvEvTac and 129X1/SvJ|
|Molecular Note||RT-PCR confirmed that five 129 substrains (129X1/SvJ, 129S1/SvImJ, 129S2/SvPas, 129S6/SvEvTac and 129P3/J) express a transcript that lacks exon 7 (delta110 isoform). Sequencing identified a 5 bp deletion in exon 7 that results in the fusion of exon 6 and 8, a frame-shift after proline 304 and a stop codon after 5 aberrant amino acids. This deletion is not present in C57BL/6. Western blot analysis confirmed the absence of protein expression in LPS-primed macrophage.|
A footpad injection of Complete Freund's Adjuvant (CFA) administered once at weaning will delay diabetes onset, thus extending the lifespan of breeders. A discussion on the use of Complete Freund's Adjuvant in NOD mice can be found in Current Protocols in Immunology (1997) pages 15.9.1-15.9.23 (see PDF link under Immunological protocols).
When using the ICE mouse strain in a publication, please cite the originating article(s) and include JAX stock #004947 in your Materials and Methods section.