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Phenotypes Associated with This Genotype
Genotype
MGI:3513191
Allelic
Composition
Plectm1Gwi/Plectm1Gwi
Genetic
Background
involves: 129S1/Sv * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Plectm1Gwi mutation (0 available); any Plec mutation (79 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• homozygotes die between day 1 and 3 after birth

cardiovascular system
• light microscopy reveals no overt anomalies in the myocardium, atrial and ventricular walls; no necrotic cardiomyocytes are observed
• however, in affected cells, sarcomeres appear loosely and irregularly arranged relative to wild-type
• in addition, aberrant isolated myofibril bundles and accumulation of Z-band material are observed
• ultrastructurally, mutant cardiomyocytes show partial disintegration of intercalated discs and adjacent myofibers
• large blisters are often accompanied by bleedings, particularly at the extremities, suggesting disruption of vascular endothelial cells

growth/size/body
• postnatally, most homozygotes are smaller than wild-type littermates, as a result of reduced gain in body weight

muscle
• light microscopy reveals no overt anomalies in the myocardium, atrial and ventricular walls; no necrotic cardiomyocytes are observed
• however, in affected cells, sarcomeres appear loosely and irregularly arranged relative to wild-type
• in addition, aberrant isolated myofibril bundles and accumulation of Z-band material are observed
• ultrastructurally, mutant cardiomyocytes show partial disintegration of intercalated discs and adjacent myofibers
• although all muscle groups show pathological changes, the paravertebral and distal limb muscles are preferentially affected
• focal disruptions of sarcomeres affecting Z-lines and adjacent myofibrils are frequently observed
• in affected areas, mutant Z-lines appear loose, with a poorly focused, smearing and streaming appearance
• overall, the sarcolemma remains structurally intact, except for occasional short ruptures of the plasma membrane
• degenerating, necrotic changes of various degrees are found in 0.5%-1% of single mutant muscle fibers versus less than 0.1% found in wild-type
• myophagocytosis is occasionally observed in association with necrotic fibers
• necrotic changes involving focal loss of myofilaments of various degrees are noted in ~20% of muscle fibers; no apoptotic events are observed in the nuclei of muscle cells
• mutants show abnormalities that resemble minicore myopathies in skeletal muscle and disintegration of intercalated discs in heart

integument
• the mutant skin is detached at the fore- and hindlimbs and sometimes around the mouth and nasal cavities
• parts of the basal lamina overlying the dermis are covered by a partially fragmented cell membrane, possibly a remnant of the basal cell surface membrane of keratinocytes
• disruption and degeneration of the basal epidermal cell layer is observed at the blister margins
• the number of mutant hemidesmosomes is reduced to ~50% of wild-type mice; their mechanical stability is altered
• the basal cell layer is completely absent from the upper epidermal layers that form the blister roof
• basal keratinocyte disruption occurs throughout the cytoplasm, in some instances in perinuclear regions, in others through basal or apical cytoplasmic regions
• other basal keratinocytes show granular dissolution of cytoplasmic components in spite of preservation of some mitochondria and dense bodies; in these cells, keratin filaments are not detectable
• at the center of blisters, basal keratinocytes are no longer detectable and replaced by a fluid-filled space
• mutant keratin filaments appear looser and less bundled than wild-type, esp. at their insertion site into the inner plate structure
• homozygotes exhibit large blisters (up to 1 cm in diameter) at the upper and lower extremities, often accompanied by bleeding
• in skin, large blisters are located between the dermis and the superficial epidermal layers
• smaller blisters are present at other sites of the integumentum esp. in the epithelial layers of the oral mucosa and the tongue


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Tumor Biology (MTB), Gene Ontology (GO), MouseCyc
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last database update
11/29/2016
MGI 6.06
The Jackson Laboratory