Stmn2 (stathmin-like 2) encodes a phosphoprotein that is involved in microtubule dynamics, signal transduction, and in the regulation of neuronal growth. It is one of the most abundantly expressed genes in mouse and human motor neurons. Specifically, STMN2 functions as an axonal-maintenance factor and in motor axon regeneration. TARDBP (TAR DNA binding protein) or TDP-43 is a neurofilament mRNA binding protein. TDP-43 proteinopathy is associated with multiple neurodegenerative diseases including amyotrophic lateral sclerosis, frontotemporal lobar degeneration and Alzheimer's disease. Loss of TDP-43 function affects STMN2 and produces a truncated nonfunctional mRNA in humans (mouse STMN2 lacks cryptic splice and polyadenylation sites). Chronic loss of STMN2 results in progressive motor and sensory deficits, muscle denervation, impaired recovery of human motor neurons after axonal injury, and reduced conduction velocity.
 Stmn2delEx3 knock-out mice were created using CRISPR/cas9 genome editing to delete exon 3. The deletion results in the absence of protein and a high degree of homozygous perinatal lethality with 18% of homozygotes surviving to 3 weeks (see MMRRC Stock No. <a href="https://www.jax.org/strain/033740">69524</a>). Hemizygous hSTMN2 transgenic mice express human STMN2 at 50% of wild type levels in the brain and 80% of WT levels in spinal cord. Mice hemizygous for the transgene are viable and fertile. The donating investigator does not recommend maintaining the transgene as a homozygote.
 When the Stmn2delEx3 and hSTMN2 alleles are combined such that mice are homozygous for Stmn2delEx3 and hemizygous for the human STMN2 transgene, the transgene rescues double mutant mice from the lethality phenotype.

The use of this mouse model is subject to the terms and conditions of the Limited Use Label License from Caribou Biosciences, Inc.

The use of this mouse strain or other product (the "Licensed Product") is subject to the terms and conditions of the Limited License from The Broad Institute.

Stmn2delEx3 hSTMN2 mice carry an Stmn2 (stathmin-like 2) knock-out allele and a transgene expressing human STMN2. In this strain, the presence of the transgene rescues the lethality phenotype found in Stmn2delEx3 homozygous mice (MMRRC Stock No. <a href="https://www.jax.org/strain/033740">69524</a>). This strain may be useful for research in axonal maintenance and regeneration as they relate to neurodegenerative diseases.

This strain is hosted by NIH's MMRRC, which partners with JAX for the distribution of this and other strains. For additional information and to purchase, please visit the MMRRC site.