Phenotypes associated with this allele

• Allele Symbol: Lama2^tm1Stk
• Allele Name: targeted mutation 1, Shin'ichi Takeda
• Allele ID: MGI:2153004
• Summary: 5 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Lama2^tm1Stk/Lama2^tm1Stk	involves: 129P2/OlaHsd	MGI:3789206
hm2	Lama2^tm1Stk/Lama2^tm1Stk	involves: 129P2/OlaHsd * BALB/c	MGI:3789293
hm3	Lama2^tm1Stk/Lama2^tm1Stk	involves: 129/Sv * 129P2/OlaHsd * BALB/c * ICR	MGI:3789197
cx4	Lama2^tm1Stk/Lama2^tm1Stk Lama4^tm1Ktry/Lama4^tm1Ktry	involves: 129P2/OlaHsd * 129X1/SvJ	MGI:3789289
cx5	Lama2^tm1Stk/Lama2^tm1Stk Tg(CAG-Lama1)12Mdur/0	involves: 129P2/OlaHsd * C57BL/6 * CBA	MGI:3789207

Genotype
MGI:3789206

hm1

• Allelic Composition: Lama2^tm1Stk/Lama2^tm1Stk
• Genetic Background: involves: 129P2/OlaHsd

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

reproductive system

abnormal spermatid morphology ( J:100711 )

♂ • fewer spermatid are detected by protamine-2 staining compared to in wild-type mice

abnormal testis morphology ( J:100711 )

♂ • at day 23, no sperm flagellum are detected in the testis

♂ • the basement membrane underlying Sertoli cells is thinner and disrupted compared to in wild-type mice

abnormal seminiferous tubule morphology ( J:100711 )

♂ • small or no lumens form in the seminiferous tubules unlike in wild-type mice

endocrine/exocrine glands

abnormal testis morphology ( J:100711 )

♂ • at day 23, no sperm flagellum are detected in the testis

♂ • the basement membrane underlying Sertoli cells is thinner and disrupted compared to in wild-type mice

abnormal seminiferous tubule morphology ( J:100711 )

♂ • small or no lumens form in the seminiferous tubules unlike in wild-type mice

cellular

abnormal spermatid morphology ( J:100711 )

♂ • fewer spermatid are detected by protamine-2 staining compared to in wild-type mice

abnormal basement membrane morphology ( J:100711 )

• the basement membrane underlying Sertoli cells is thinner and disrupted compared to in wild-type mice

Genotype
MGI:3789293

hm2

• Allelic Composition: Lama2^tm1Stk/Lama2^tm1Stk
• Genetic Background: involves: 129P2/OlaHsd * BALB/c

immune system

thymus cortex hypoplasia ( J:61802 )

• the cortex is thin with few thymocytes

abnormal thymus corticomedullary boundary morphology ( J:61802 )

• the cortico-medullary junction is obscured

abnormal thymus physiology ( J:61802 )

• unlike in wild-type mice, many apoptotic cells are present in the subcapsular and outer cortical areas of the thymus

decreased T cell number ( J:61802 )

• total numbers of thymic and splenic T cells are reduced

decreased double-positive T cell number ( J:61802 )

• the number of double positive thymocytes is decreased compared to in wild-type mice likely due to increased apoptosis

hematopoietic system

thymus cortex hypoplasia ( J:61802 )

• the cortex is thin with few thymocytes

abnormal thymus corticomedullary boundary morphology ( J:61802 )

• the cortico-medullary junction is obscured

abnormal thymus physiology ( J:61802 )

• unlike in wild-type mice, many apoptotic cells are present in the subcapsular and outer cortical areas of the thymus

decreased T cell number ( J:61802 )

• total numbers of thymic and splenic T cells are reduced

decreased double-positive T cell number ( J:61802 )

• the number of double positive thymocytes is decreased compared to in wild-type mice likely due to increased apoptosis

endocrine/exocrine glands

thymus cortex hypoplasia ( J:61802 )

• the cortex is thin with few thymocytes

abnormal thymus corticomedullary boundary morphology ( J:61802 )

• the cortico-medullary junction is obscured

abnormal thymus physiology ( J:61802 )

• unlike in wild-type mice, many apoptotic cells are present in the subcapsular and outer cortical areas of the thymus

Genotype
MGI:3789197

hm3

• Allelic Composition: Lama2^tm1Stk/Lama2^tm1Stk
• Genetic Background: involves: 129/Sv * 129P2/OlaHsd * BALB/c * ICR

mortality/aging

premature death ( J:43145 )

• mice die of undetermined causes by 5 weeks of age

muscle

abnormal skeletal muscle morphology ( J:43145 )

• by P21 and P28, proliferation of endomysial connective tissue is observed

abnormal skeletal muscle fiber morphology ( J:43145 )

• the number of apoptotic nuclei in muscle fibers is increased compared to in wild-type mice

increased variability of skeletal muscle fiber size ( J:43145 )

• by P21 and P28, muscle fibers of different calibers are apparent

dystrophic muscle ( J:43145 )

• by P24 mice exhibit dystrophic symptoms including a waddling gait and twitching

muscle spasm ( J:43145 )

• by P24 mice exhibit twitching

myopathy ( J:43145 )

• by P9 mice exhibit scattered degeneration of muscle fibers and at P11 numerous degenerating fibers with extensive infiltrate are observed

• degeneration is accompanied by regeneration at P13

behavior/neurological

abnormal gait ( J:43145 )

• by P24 mice exhibit a waddling gait

growth/size/body

decreased body size ( J:43145 )

• beginning at P14 and continuing for the rest of their lives

postnatal growth retardation ( J:43145 )

• apparent after postnatal day 14

cellular

abnormal basal lamina morphology ( J:43145 )

• the basal lamina is nearly completely absent around muscle fibers and Schwann cells of peripheral nerves

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
congenital merosin-deficient muscular dystrophy 1A		DOID:0110636	OMIM:607855	J:43145 , J:167230

Genotype
MGI:3789289

cx4

• Allelic Composition: Lama2^tm1Stk/Lama2^tm1Stk; Lama4^tm1Ktry/Lama4^tm1Ktry
• Genetic Background: involves: 129P2/OlaHsd * 129X1/SvJ

mortality/aging

postnatal lethality, complete penetrance ( J:98086 )

• while appearing normal at birth and suckling effectively, mice die by P13

nervous system

decreased Schwann cell number ( J:98086 )

• proliferating Schwann cells in E17 mice is decreased

abnormal axon radial sorting ( J:98086 )

• at P11, mice exhibit a near complete absence of radial sorting of spinal nerve roots and distal nerves

Genotype
MGI:3789207

cx5

• Allelic Composition: Lama2^tm1Stk/Lama2^tm1Stk; Tg(CAG-Lama1)12Mdur/0
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6 * CBA

reproductive system

reproductive system phenotype ( J:100711 )

N • mice are capable of reproduction and exhibit a rescue of the reproductive defects observed in Lama2^tm1Stk homozygotes