FVB.Cg-Grm7^{Tg(SMN2)89Ahmb} Smn1^tm1Msd Tg(Prnp-PLS3)14Ahmb Tg(SMN2*delta7)4299Ahmb/J

Stock number: 030214
Product name: PLS-14;SMN2;Δ7SMN;Smn- (or PLS_14, Smn+/-) (or PrP:PLS3^+/-;SMN2^+/+;Δ7SMN^+/+;Smn^+/-)
Strain synonyms: PLS-14^+/-;SMN2^+/+;Δ7SMN^+/+;Smn^+/-
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

PrP:PLS3 SMA mice from founder line 14 (PLS-14;SMN2;Δ7SMN;Smn-) that are homozygous for the Smn1 null allele, homozygous for the Tg(SMN2)89Ahmb transgene and homozygous for the Tg(SMN2*delta7)4299Ahmb transgene exhibit symptoms and neuropathology similar to patients afflicted with proximal spinal muscular atrophy (SMA) - regardless of presence or absence of the Tg(Prnp-PLS3)14Ahmb) transgene.

 

Detailed description

PrP:PLS3 SMA mice from founder line 14, called PLS-14;SMN2;Δ7SMN;Smn-, harbor the Smn1 null allele (Smn1^tm1Msd) and three transgenic alleles. The Tg(SMN2)89 transgene sequence encoding the entire human SMN2 gene is inserted into the glutamate receptor metabotropic 7 locus (Grm7^{Tg(SMN2)89Ahmb}) on chromosome 6. The Tg(SMN2*delta7)4299Ahmb transgene consists of a SMA cDNA lacking exon 7. The Tg(Prnp-PLS3)14Ahmb transgene has human plastin 3 protein (PLS3) overexpression directed to neurons by the mouse prion protein regulatory sequences.

FVB/N-congenic mice homozygous for Grm7^{Tg(SMN2)89Ahmb}, Smn1^tm1Msd and Tg(SMN2*delta7)4299Ahmb - called SMN2^+/+;Smn^-/-;Δ7SMN^+/+ - exhibit symptoms and neuropathology similar to patients afflicted with proximal spinal muscular atrophy (SMA). Their detailed phenotype is as described for Stock No. 005025.

These PLS-14;SMN2;Δ7SMN;Smn- mice (Stock No. 030214) harbor the same Smn1 null allele and two transgenes as Stock No. 005025, but also have the Tg(Prnp-PLS3)14Ahmb transgene. For SMN2^+/+;Smn^-/-;PLS-14^+/-;Δ7SMN^+/+ animals (now hemizygous for the PLS-14 transgene), the PLS3 transcript level is increased ~100-fold in motor neurons - which translated to ~2-fold increased PLS3 protein levels in total spinal cord. Despite this PLS3 overexpression, there was no significant beneficial effect on their SMA phenotype. Specifically, neither survival nor the fundamental electrophysiological aspects of the neuromuscular junction were improved upon overexpression of PLS3 in neurons. The median survival of SMN2^+/+;Smn^-/-;PLS-14^+/-;Δ7SMN^+/+ mice was ~15 days of age.

PLS-14;SMN2;Δ7SMN;Smn- mice homozygous for Grm7^{Tg(SMN2)89Ahmb}, heterozygous for Smn1^tm1Msd, hemizygous for Tg(Prnp-PLS3)14Ahmb and homozygous for Tg(SMN2*delta7)4299Ahmb - called SMN2^+/+;Smn^+/-;PLS-14^+/-;Δ7SMN^+/+ - are phenotypically normal and do not exhibit symptoms of neuropathology.
However, SMN2^+/+;Δ7SMN^+/+;Smn^+/- mice are not viable when homozygous for PLS-14.

Development

These PrP:PLS3 SMA mice from founder line 14, called PLS-14;SMN2;Δ7SMN;Smn- (or PLS_14, Smn+/- or PLS-14^+/-;SMN2^+/+;Δ7SMN^+/+;Smn^+/-) harbor several mutant alleles/transgenes.

The Smn1 null targeted mutation (Smn1^tm1Msd) on chromosome 13 was created in the laboratory of Dr. Michael Sendtner (University of Wurzburg, Germany). The Tg(SMN2)89 transgene insertion into the glutamate receptor metabotropic 7 locus (Grm7^{Tg(SMN2)89Ahmb}) on chromosome 6 as well as the randomly integrated Tg(SMN2*delta7)4299Ahmb transgene were both created in the laboratory of Dr. Arthur H. M. Burghes (The Ohio State University). Each are described for FVB.Cg-Grm7^{Tg(SMN2)89Ahmb} Smn1^tm1Msd Tg(SMN2*delta7)4299Ahmb/J (Stock No. 005025).

The PrP:PLS3 transgene was created in the laboratory of Dr. Burghes to have the regulatory sequences from mouse prion protein gene (PrP or Prnp; the promoter region, exon 1, intron 1 and part of exon 2) followed by a cDNA encoding the human plastin 3 protein (PLS3) and two SV40 polyA signals. The transgene construct was injected into the pronucleus of fertilized FVB/N SMNΔ7;SMN2;Smn- mouse oocytes (from Stock No. 005025). Female founder mouse 14 (PLS-14) would not breed; therefore an ovary transfer was performed into a FVB/N female, and then progeny were bred to FVB/N SMNΔ7;SMN2;Smn- mice to establish the colony. Multiple PrP:PLS3 transgene insertion sites were not detected in line PLS-14 (although the transgene copy number not characterized).

The PLS-14;SMN2;Δ7SMN;Smn- colony was maintained on the FVB/N genetic background for several generations, and then albino mice were sent to The Jackson Laboratory Repository in 2017. Upon arrival, mice were bred to Stock No. 005025 for at least one generation.

In 2017, a 48 SNP (single nucleotide polymorphism) panel analysis, with markers covering all 19 chromosomes and the X chromosome was performed on the first generation rederived living colony at The Jackson Laboratory Repository. This revealed 1 marker on chromosome 12 was segregating for FVB and C57BL/6 allele-type. In addition, 3 markers were segregating for FVB and 129S;C57BL/6 allele-type markers (one marker each on chromosomes 8, 13 and 14) - which is consistent with that of the Stock No. 005025 mice they were first bred to.

Allele

Symbol: Tg(SMN2*delta7)4299Ahmb
Name: transgene insertion 4299, Arthur H M Burghes
MGI accession ID: MGI:3056918
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: SMNdelta7; Tg(SMN1*delta7)4299Ahmb
Marker symbol: Tg(SMN2*delta7)4299Ahmb
Marker name: transgene insertion 4299, Arthur H M Burghes
Marker synonyms: SMNdelta7; Tg(SMN1*delta7)4299Ahmb
Chromosome: UN
Strain of origin: FVB/N
Expressed genes: SMN2,survival of motor neuron 2, centromeric,human
Site of expression: Tg(SMN2*delta7)4299Ahmb
Molecular note: The transgene contains a human SMN2 promoter and a human SMN2 cDNA (SMNdelta7) that lacks exon 7. There are 14 copies of this allele integrated into the genome.

Allele

Symbol: Grm7^{Tg(SMN2)89Ahmb}
Name: transgene insertion 89, Arthur H M Burghes
MGI accession ID: MGI:2448989
Generation method: Transgenic
Attributes: Hypomorph; Inserted expressed sequence; Humanized sequence
Synonyms: SMN2; Tg(SMN2)89Ahmb
Marker symbol: Grm7
Marker name: glutamate receptor, metabotropic 7
Marker synonyms: 6330570A01Rik; E130018M02Rik; GLUR7; Gpr1g; GPRC1G; MGLU7; mGlu7a receptor; mGluR7; NEDSHBA; PPP1R87
Chromosome: 6
Strain of origin: FVB/N
Expressed genes: SMN2,survival of motor neuron 2, centromeric,human
Site of expression: Human SMN2 protein is expressed in the tissues examined (brain, liver, spinal cord) [Stock No. 005024].
Molecular note: A 35.5 kb genomic fragment containing the human survival motor neuron 2 (SMN2) gene and promoter was used for the transgene. The transgene is ubiquitously expressed in all tissues examined by Northern blot analysis. Line 89 carries 1 copy of the transgene integrated into intron 4 of the gene. RT-PCR confirmed reduced expression of the gene the transgene is integrated into.

Allele

Symbol: Smn1^tm1Msd
Name: targeted mutation 1, Michael Sendtner
MGI accession ID: MGI:2183946
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Synonyms: SMN^-
Marker symbol: Smn1
Marker name: survival motor neuron 1
Marker synonyms: BCD541; C-BCD541; GEMIN1; SMA; SMA@; SMA1; SMA2; SMA3; SMA4; Smn; SMNC; SMNT; T-BCD541; TDRD16A; TDRD16B
Chromosome: 13
Strain of origin: 129P2/OlaHsd
Expressed genes: lacZ,beta-galactosidase,E. coli
Site of expression: The expression of the lacZ gene in tissues where Smn is normally expressed was noted.
Molecular note: A lacZ-neo cassette was inserted into exon 2 by homologous recombination resulting in an in-frame fusion of lacZ to exon 2. Homozygous mutant embryos were identified up to 80 hours post coitum. The expression of the lacZ gene in tissues where Smn is normally expressed was noted.

Allele

Symbol: Tg(Prnp-PLS3)14Ahmb
Name: transgene insertion 14, Arthur H M Burghes
MGI accession ID: MGI:6121381
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: PrP:PLS3
Marker symbol: Tg(Prnp-PLS3)14Ahmb
Marker name: transgene insertion 14, Arthur H M Burghes
Chromosome: UN
Strain of origin: FVB/N
Expressed genes: PLS3,plastin 3,human
Site of expression: PLS3 is overexpressed in motor neurons of the spinal cord.
Molecular note: The transgenic construct contains the regulatory sequences from mouse prion protein gene (the promoter region, exon 1, intron 1 and part of exon 2) followed by a cDNA encoding the human plastin 3 protein and two SV40 polyA signals.