C57BL/6-Nrg1^tm1.1Dtal/J

Stock number: 040044
Product name: Nrg1 V321L

Research areas: Neurobiology Research, Research Tools, Sensorineural Research

Description

V₃₂₁L knock-in mice have V321L introduced into the Nrg1 (neuregulin 1) gene. Homozygous V₃₂₁L mutants are viable and fertile, with no outward morphological or growth abnormalities. However, mice show histologically altered adult neurogenesis in the dentate gyrus. They also show sensorimotor gating deficits and elevated startle response phenotypes. The model may be useful in studies of NRG1 functions in neurodevelopment, retinal degeneration, and maintenance of peripheral synapses.

Detailed description

Nrg1 (neuregulin 1) encodes one of four members of the neuregulin family and is known to interact with NEU/ERBB2 receptors. Nrg1 produces multiple isoforms that are expressed in excitatory and inhibitory neurons. The type III isoform contains a cysteine-rich-domain (CRD) and is the predominant isoform expressed at all rostral-caudal levels of the spinal cord through birth.

V₃₂₁L knock-in mice have V321L human psychosis-associated mutation (gtg-->ttg) introduced into the neuregulin 1 (Nrg1) gene. The mutation is in the Nrg1 transmembrane domain that disrupts nuclear back signaling with minimal effects on forward signaling or local back signaling. Homozygous V₃₂₁L mutants are viable and fertile. However, mice show histologically altered adult neurogenesis in the dentate gyrus (DG). They also show sensorimotor gating deficits and elevated startle response phenotypes. The V321L mutation impairs nuclear translocation of the Nrg1 intracellular domain (ICD) and alters gene expression in the DG. V₃₂₁L mice show reduced stem cell proliferation, altered cell cycle dynamics, fate specification defects, and dendritic dysmorphogenesis. The model may be useful in studies of Nrg1 functions in neurodevelopment, retinal degeneration, and maintenance of peripheral synapses.

Of note, in addition to these mice, The Jackson Laboratory Repository has Nrg1 KO mice (Stock No. 037094).

Development

The BAC clone (RP23:319D24) was used for generating the 9554 bp targeting construct corresponding to a region of the Nrg1 gene that comprises the entire Type III coding region spanning exons 7 to 17. The construct was designed to insert a V321L (gtg-->ttg) in exon 13 encoding a common C-terminal transmembrane domain and includes a 5.8 kbp left homology arm and reverse-oriented Frt-flanked neomycin cassette in the following intron and a 2.5 kbp right homology arm of the Nrg1 (neuregulin 1) gene on chromosome 8. The Nrg1-201, 3049 bp transcript (ENSMUST00000073884.7) was used for reference. V321L is the change in both human and mouse. The numbering is based on the Type III Nrg1-beta-1a isoform. In addition to the V321L (gtg-->ttg) mutation in exon 13, a silent G to A transition that removes a Sac 1 cleavage site (72 bp 5' of the G to T mutation that introduces the V to L mutation) was introduced. The mutation was introduced into the BAC clone by overlap extension PCR and verified by sequencing in the targeting construct. The construct was electroporated into C57BL/6-derived unspecified embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts. The resulting chimeric mice were bred to unknown Flp recombinase-expressing mice on a C57BL/6 genetic background to establish germline transmission and excise the FRT-flanked neo-selection cassette. The resulting mice with the V₃₂₁L allele were mated to C57BL/6J mice (Stock No. 000664) to establish the colony and mice were subsequently bred to homozygosity by the donating laboratory (see SNP note below). Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes.

In 2025, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the males sent to The Jackson Laboratory Repository. Three of the 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Nrg1^tm1.1Dtal
Name: targeted mutation 1.1, David A Talmage
MGI accession ID: MGI:7855141
Generation method: Targeted
Attributes: Humanized sequence
Synonyms: Nrg1^tm1DatV/L; Nrg1tm1Dat V/L; V321L
Marker symbol: Nrg1
Marker name: neuregulin 1
Marker synonyms: 6030402G23Rik; ARIA; D230005F13Rik; GGF; GGF2; GGFII; heregulin; HGL; HRG; HRG1; HRGA; HRGalpha; MST131; MSTP131; NDF; NRG1-IT2; SMDF
Chromosome: 8
Strain of origin: C57BL/6
Molecular note: The knock-in germline V321L mutation (gtg→ttg) in mice Nrg1 gene was introduced into embryonic stem cells using a bacterial artificial chromosome (BAC) construct. Frt flanked neo cassette was removed by Flp recombinase.