Homozygous knock-out mice display abnormal mossy fiber morphology, increased exploration in new environment and impaired fear responses.
Jamey D Marth, Burnham Inst at Univ Calif Santa Barbara
Heterozygous mice are viable and fertile and do not display any gross physical or behavioral abnormalities. Homozygous mice show a polysialic acid (PSA) deficit in regions of neurogenesis. Hippocampal synaptic plasticity is not impaired, but abnormal trafficking of infrapyramidal mossy fibers and the formation of ectopic synapses in the hippocampus are observed coincident with a high exploratory drive and reduced behavioral responses to Pavlovian fear conditioning.
This mutant mouse strain represents a model of polysialyltransferase function in modulating axonal trafficking and mechanisms of anxiety and fear behaviors.
A targeting vector was used to place a floxed neomycin-thymidine kinase expression cassette in the intron upstream of exon 4 and a lox P site in the intron downstream of exon 4. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl +-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were transfected with a Cre expression plasmid to excise the floxed regions. Gancyclovir-resistant ES cells were injected into C57BL/6 blastocysts. Chimeric animals were crossed with C57BL/6 at least 6 generations by the donating laboratory.
|Allele Name||targeted mutation 1, Jamey Marth|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||St8sia2, ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 2|
|Strain of Origin||Not Specified|
|Molecular Note||Exon 4, encoding a significant portion of the sailyl motif L, was deleted upon Cre mediated deletion of the floxed region including the exon and a tk-neo cassette. Southern blot confirmed recombination and RT-PCR indicated that the truncated form of mRNA was produced in heterozygous and homozygous mutants. The mutant cDNA was found to be inactive.|
|Mutations Made By|| |
Jamey Marth, Burnham Inst at Univ Calif Santa Barbara
When maintained as a live colony, heterozygous crosses may be used.
When using the ST8Sia-II KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #006902 in your Materials and Methods section.