HSP^S139F knock-in (KI) mice harbor a CRISPR/Cas9-generated point mutation in the Hspb1 gene resulting in a serine to phenylalanine substitution. This mutation corresponds to the human clinical missense mutation S135F, which is common in Charcot-Marie-Tooth disease type 2F (CMT2F) patients. This mouse model may be useful when studying hereditary and sensory neuropathies, such as CMT2F.

Not applicable

Heat shock protein beta-1 (HSPB1), also called heat shock protein 27, is a member of the heat shock protein family known to help maintain cellular protein homeostasis under adverse conditions. This particular protein plays an important role in cell differentiation, regulation of apoptotic signaling, assisting in folding and stabilizing newly produced proteins, and repairing damaged proteins. HSPB1 is highly expressed in nerve and muscle cells and is also implicated in regulating neurofilament structure and function, as well as muscle contraction. Mutations in the Hspb1 gene have been associated with peripheral neuropathies such as Charcot-Marie-Tooth (CMT) disease. These HSP^S139F knock-in (KI) mice harbor a CRISPR/Cas9-generated point mutation in the Hspb1 gene resulting in a serine to phenylalanine substitution. This mutation corresponds to the human clinical missense mutation S135F, which is common in CMT type 2F patients.

Homozygous HSP^S139F KI mice are viable and fertile; however, homozygous mice do demonstrate cerebellar demyelination as well as coordination and muscle strength deficits compared to wildtype controls by 3 months of age. These HSP^S139F KI mice may be useful when studying hereditary and sensory neuropathies, such as CMT type 2F.

The HSP^S139F knock-in allele was generated using CRISPR/Cas9 endonuclease-genome editing at The Jackson Laboratory. A guide RNA [5'-GAACATGGCTACATCTCT-3'] was selected to introduce a point mutation (TCT to TTT) in the heat shock protein 1 (Hspb1) locus on chromosome 5. Transcript Hspb1-201 (ENSMUST00000005077.7) was used as reference for the exon number and guide sequence. Cas9 nuclease mRNA, sgRNA and a DNA donor template sequence were introduced into the cytoplasm of zygotes derived from C57BL/6J mice with well recognized pronuclei. Correctly targeted pups were identified by PCR and Sanger sequencing. The resulting founder mice were crossed to C57BL/6J mice for 1 generation before intercrossing heterozygous mice. Note that all founder lines produced were found to carry an off-target event in a pseudogene on Chromosome 13 (Hsp25-ps1); the donating laboratory established this HSP^S139F mouse line using only mice that carried the HSP^S139F allele and the wildtype (WT) form of Hsp25-ps1. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes.

C57BL/6J

The MMRRC Centers have developed a genetic QC pipeline using MiniMUGA array genotyping to provide additional information on strain backgrounds for MMRRC congenic and inbred strains. For more information on when data may be available, or to request genotyping for a strain of interest, please contact csmmrrc@jax.org. Older strains may not have this information.

Ben Low, The Jackson Laboratory.