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Phenotypes Associated with This Genotype
Genotype
MGI:7444862
Allelic
Composition
Lemd2em1Eno/Lemd2em1Eno
Genetic
Background
involves: C3H * C57BL/6 * C57BL/6N
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Lemd2em1Eno mutation (0 available); any Lemd2 mutation (20 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• mice subjected to acute beta-adrenergic stimulation using isoproterenol show severe atrioventricular (AV) blocks and die before the end of the experiment
• mice have a median life span of 20 weeks

cardiovascular system
• 3-fold increase in the number of gamma-H2AX+ nuclei in cardiac sections indicating an increase in the number of DNA double-strand breaks and an increase in expression of genes related to DNA damage indicating presence of genotoxic stress and DNA damage in hearts
• mice develop cardiac phenotypes early in life, with the main structural and functional cardiac parameters altered by 3 weeks after birth
• electron-dense nuclear envelope-associated heterochromatin is almost absent in more than 30% of nuclei, indicating chromatin abnormalities
• cardiomyocytes from 2-month-old mice show increases in length, width, and area
• however, cardiac sections show normal sarcomere ultrastructure
• hearts show severe dilation of the atrial chambers at 3 months of age
• hearts show severe dilation of the ventricular chambers at 3 months of age
• mice show severe dilated cardiomyopathy, characterized by cardiac chamber dilation and reduced ventricular wall thickness
• however, heart weight normalized to tibia length is normal
• ejection fraction is half that of wild-type mice and fractional shortening is reduced
• however, isolated cardiomyocytes exposed to electrical stimulation (pacing) show normal length of sarcomeres, fractional shortening, diastolic calcium levels, and transient amplitude and time to calcium peak
• echocardiography shows a decrease in systolic left ventricular anterior wall thickness and a 3-fold increase in systolic left ventricular internal diameter, ejection fraction that is half that of wild-type mice, and reduced fractional shortening
• cardiac electrical alterations worsen to a type II AV block in a subset of mice, in which P waves are not followed by a QRS complex
• mice subjected to acute beta-adrenergic stimulation using isoproterenol show severe AV blocks and die before the end of the experiment
• ECG shows cardiac electrical alterations characterized by an increased P-R interval, suggesting delayed conduction of the electrical signal from the atria to the ventricles through the AV node
• however, no alterations in cardiac rhythm or correct QT duration are seen under basal conditions and morphology and size of the AV node are similar to wild-type

homeostasis/metabolism
• mice subjected to acute beta-adrenergic stimulation using isoproterenol show severe atrioventricular (AV) blocks and die before the end of the experiment

muscle
N
• no abnormalities in different skeletal muscle groups are seen, including no difference in skeletal muscle weight
• electron-dense nuclear envelope-associated heterochromatin is almost absent in more than 30% of nuclei, indicating chromatin abnormalities
• cardiomyocytes from 2-month-old mice show increases in length, width, and area
• however, cardiac sections show normal sarcomere ultrastructure
• mice show severe dilated cardiomyopathy, characterized by cardiac chamber dilation and reduced ventricular wall thickness
• however, heart weight normalized to tibia length is normal
• ejection fraction is half that of wild-type mice and fractional shortening is reduced
• however, isolated cardiomyocytes exposed to electrical stimulation (pacing) show normal length of sarcomeres, fractional shortening, diastolic calcium levels, and transient amplitude and time to calcium peak

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
cardiomyopathy DOID:0050700 J:331716


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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last database update
10/29/2024
MGI 6.24
The Jackson Laboratory