Phenotypes associated with this allele

• Allele Symbol: Bdnf^tm1Tbn
• Allele Name: targeted mutation 1, Tobias Bonhoeffer
• Allele ID: MGI:1891516
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Bdnf^tm1Tbn/Bdnf^tm1Tbn	involves: 129S2/SvPas	MGI:3764504
hm2	Bdnf^tm1Tbn/Bdnf^tm1Tbn	involves: 129S4/SvJae * NMRI	MGI:2175723
ht3	Bdnf^tm1Tbn/Bdnf^+	involves: 129S4/SvJae * NMRI	MGI:2175724

Genotype
MGI:3764504

hm1

• Allelic Composition: Bdnf^tm1Tbn/Bdnf^tm1Tbn
• Genetic Background: involves: 129S2/SvPas

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

nervous system

abnormal sympathetic system morphology ( J:56217 )

• abnormal sympathetic innervation; adrenergic hypoinnervation in the dorsal skin

abnormal innervation ( J:56217 )

• abnormal sympathetic innervation; adrenergic hypoinnervation in the dorsal skin

abnormal adrenergic neuron morphology ( J:56217 )

• reduction in the number of dermal adrenergic fibers

integument

abnormal keratinocyte morphology ( J:54992 )

• reduced numbers of proliferating epidermal keratinocytes

Genotype
MGI:2175723

hm2

• Allelic Composition: Bdnf^tm1Tbn/Bdnf^tm1Tbn
• Genetic Background: involves: 129S4/SvJae * NMRI

mortality/aging

postnatal lethality, complete penetrance ( J:64962 )

• homozygotes usually die between 2 and 4 weeks of age

endocrine/exocrine glands

abnormal colon goblet cell morphology ( J:110612 )

• enlarged goblet cells

growth/size/body

decreased body weight ( J:64962 )

• at >P3, homozygotes display a 75% reduction in body weight relative to wild-type mice

postnatal growth retardation ( J:64962 )

• at P3 or later, homozygotes are growth retarded relative to wild-type littermates

behavior/neurological

impaired balance ( J:64962 )

impaired limb coordination ( J:64962 )

nervous system

abnormal cochlear OHC afferent innervation pattern ( J:84871 )

• type II afferent fibers lacking at birth and first post natal week in the medial and apical turns of the cochlea but they are present in the basal turn

• at age 19 days the pattern is reversed

decreased sensory neuron number ( J:64962 )

• homozygotes exhibit a loss of neurons in the dorsal root ganglia

small dorsal root ganglion ( J:64962 )

• homozygotes exhibit a loss of neurons in the dorsal root ganglia

impaired synaptic plasticity ( J:64962 )

• frequency distributions of posttetanic synaptic enhancements indicate that in homozygotes most potentiations are close to 100% vs >150% in wild-type mice

abnormal excitatory postsynaptic potential ( J:64962 )

• after tetanic stimulation, homozygotes exhibit significantly reduced mean field EPSP slopes relative to wild-type mice, even when only successful LTPs are included

• in contrast, paired pulse facilitation (ratio of second EPSP slope to first EPSP slope) is unaffected

reduced long-term potentiation ( J:64962 )

• homozygotes show almost no LTP in the CA1 region of the hippocampus until P16 (only 1 successful LTP in 19 slices; 5%)

• from P17 to P28, the % of successful LTPs rises to 32.6%, but the magnitude is significantly smaller than in wild-type mice and declines slowly over time

• notably, general hippocampus anatomy and hippocampal pyramidal neuron morphology and pharmacology appear to be normal

digestive/alimentary system

abnormal intestine morphology ( J:110612 )

• generally hypotrophic

• mucosal layers of ileum and duodenum are normal

abnormal colon morphology ( J:110612 )

• mucosal atrophy

abnormal colon goblet cell morphology ( J:110612 )

• enlarged goblet cells

hearing/vestibular/ear

abnormal cochlear OHC afferent innervation pattern ( J:84871 )

• type II afferent fibers lacking at birth and first post natal week in the medial and apical turns of the cochlea but they are present in the basal turn

• at age 19 days the pattern is reversed

integument

abnormal hair cycle ( J:53271 )

• after 22 days, most hair follicles in later stages of regression (catagen) while controls are at the end of catagen or in the resting phase (telogen)

cellular

abnormal colon goblet cell morphology ( J:110612 )

• enlarged goblet cells

Genotype
MGI:2175724

ht3

• Allelic Composition: Bdnf^tm1Tbn/Bdnf⁺
• Genetic Background: involves: 129S4/SvJae * NMRI

nervous system

impaired synaptic plasticity ( J:64962 )

• frequency distributions of posttetanic synaptic enhancements indicate that in heterozygotes most potentiations are close to 100% vs >150% in wild-type mice

• after P16, heterozygotes display almost no differences in posttetanic synaptic strengthening relative to homozygotes

abnormal excitatory postsynaptic potential ( J:64962 )

• after tetanic stimulation, heterozygotes exhibit a similar reduction in mean field EPSP slopes to that observed in homozygotes

• as in homozygotes, paired pulse facilitation (ratio of second EPSP slope to first EPSP slope) is unaffected

reduced long-term potentiation ( J:64962 )

• heterozygotes display a similar reduction in LTP magnitude and % of successful LTPs in the CA1 region of the hippocampus to that observed in homozygotes

• again, the magnitude of potentiation is significantly smaller than in wild-type mice and declines slowly over time

• in contrast to homozygotes, heterozygotes are viable and display normal dorsal root ganglia and no balance or coordination deficits