STOCK Ntn5^tm1.1Rwb/Rwb

Stock number: 005592
Research areas: Developmental Biology Research, Neurobiology Research

Description

Mice homozygous for this deletion have ectopic motor neurons that migrate out of the ventral horn and into the motor roots, with more ectopias in the rostral than the caudal end. This strain is valuable in the characterization of netrin family signaling and neuronal development.

Detailed description

Mice homozygous for this deletion have ectopic motor neurons that migrate out of the ventral horn and into the motor roots, with more ectopias in the rostral than the caudal end. These ectopic neurons do not express neuropilin 2. Despite the ectopic motor neurons, homozygotes are overtly normal, with normal body size, life span, fertility, gait, grip strength, and general motor activity, and no aberrant phenotypes detected in the Knockout Mouse Phenotyping (KOMP2) assessment performed at The Jackson Laboratory. Although Ntn5 is expressed in boundary cap cells, it is not required for their development as boundary cells are present in homozygotes. The trigeminal nerve is normal, dorsal root ganglia and their sensory inputs into the dorsal spinal cord are normal, and no nociceptive defects were detected by either von Frey or hot plate testing.

Development

Using homologous recombination in R1 ES cells, exons 2-6 were replaced with farnysylated YFP fused to the 5-prime sequence of exon2 and an FRT-flanked neomycin resistance cassette and the resulting mice were bred to B6.Cg-Tg(ACTFLPe)9205Dym/J to excise the neomycin resistance cassette. Although sequencing confirmed that the integrated YFPF is in-frame with the start site, no expression was detected by either endogenous fluorescence or antibody staining. This strain was crossed to C57BL/6J for approximately 3 generations before being maintained by sibling intercrossing primarily homozygotes.

Allele

Symbol: Ntn5^tm1.1Rwb
Name: targeted mutation 1.1, Robert W Burgess
MGI accession ID: MGI:5701693
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Ntn5
Marker name: netrin 5
Chromosome: 7
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: Exons 2-6 were replaced with a cassette encoding a farnysylated YFP fused to the 5-prime sequence of exon2 and an FRT-flanked neomycin resistance cassette, and subsequent flpe-mediated excision deleted the neomycin selection cassette. Although sequencing confirmed that the integrated YFPF is in-frame with the start site, no expression was detected by either endogenous fluorescence or antibody staining. Although this deletion is also in intron 1 of Sec1, Q-RT-PCR did not detect any reduction in Sec1 expression.