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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID
Rxratm1Rev
targeted mutation 1, Ronald M Evans
MGI:1857672
Summary 2 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
Rxratm1Rev/Rxratm1Rev involves: 129S4/SvJae * C57BL/6 MGI:2176443
ht2
Rxratm1Rev/Rxra+ involves: 129S4/SvJae * C57BL/6 MGI:2176444


Genotype
MGI:2176443
hm1
Allelic
Composition
Rxratm1Rev/Rxratm1Rev
Genetic
Background
involves: 129S4/SvJae * C57BL/6
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Rxratm1Rev mutation (1 available); any Rxra mutation (24 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• homozygotes die between E13.5 and E16.5, with most embryos still viable at E14.5 but dead by E15.5

cardiovascular system
• at E14.5, only 1 of 10 homozygotes displays an abnormal aortic pulmonary septum; both aortic and pulmonary valves appear unaffected
• at E13.5, upon color fluorescent imaging, the mutant heart appears much more translucent than the wild-type heart
• 28% show incomplete aorticopulmonary septum/aorticopulmonary window
• all homozygotes display impaired differentiation or maturation of the ventricular cardiac myocytes (J:18047)
• spongy layer of the myocardium is generally thicker (J:35363)
• 67% show attenuated trabeculae and contain an unusual, random branching pattern
• by E14.5, homozygotes show absence of myocyte proliferation at the ventricular epicardial surface ("compact layer")
• 100% have abnormalities of conotruncal ridges ranging from mild deficiency of conotruncal tissue (6%) to complete absence of cushion tissue (66%)
• seen in 11% of homozygotes
• exhibit a wide spectrum of atrioventricular cushion defects
• 67% show partial fusion of the atrioventricular cushions
• complete lack of fusion of the superior and inferior atroioventricular cushions
• portion of embryos with shortened conotruncal ridges exhibit double outlet right ventricle (17%)
• 17% show cleft mitral valve
• by E14.4, 1 of 10 homozygotes displays mitral atresia; no tricuspid atresia is observed
• 17% show cleft tricuspid valve
• at E14.5, homozygotes exhibit normal atrial structure and function with no differences in overall position of heart and major vessels; however, the left atrium appears small
• at E14.5, 5 of 10 homozygotes display dilation of the right atrial chambers
• 39% show a common atrioventricular canal
• at E11.5 or later, homozygotes exhibit an uneven ventricular contour (J:18047)
• at E14.5, both ventricles exhibit a globular rather than elliptical shape, suggesting a dilated form of congestive heart failure (J:65904)
• 56% exhibit dysmorphic papillary muscles
• at E14.5, homozygotes display a poorly developed ventricular septum (J:18047)
• by E14.5, 9 of 10 homozygotes display obvious ventricular septal defects at the septal-cushion fusion (J:18047)
• 94% exhibit a ventricular septal defect, with all defects being muscular (J:35363)
• by E14.5, all (10 of 10) homozygotes show ventricular chamber hypoplasia
• by E14.5, ventricular trabeculation is present but reduced and appears disorganized at the muscular septum
• 94% exhibit a hypoplastic compact zone of the ventricular myocardium
• at E14.5, some homozygotes display dilated right ventricles
• at E14.5, all (10 of 10) homozygotes exhibit a thinned ventricular wall (J:18047)
• at E13.5, the relatively thin-walled "atrial-like" phenotype of mutant ventricular muscle cells is shown to correlate with the aberrant, persistent expression of an atrial marker (J:18047)
• by E14.5, most homozygotes show a prominent pericardial space
• at E11.5 and E12.5, homozygotes exhibit a loosely apposed pericardium; however, the pericardium appears relatively normal at E14.5
• at E13.5 and E14.5, left ventricular area ejection fractions of mutant hearts average 14% vs 50% in wild-type hearts, indicating ventricular dysfunction
• at E14.5, depressed ejection fraction is related to thinned left ventricular wall and impaired shortening of the mutant myocardium
• at E13.5, homozygotes show normal AV synchrony and display heart rates comparable to those of wild-type mice; however, mutant heart rates are slightly decreased at E14.5
• at E14.5, 2 of 10 homozygotes display a complete heart block
• by E14.5, homozygotes with slightly reduced heart rates exhibit an intermittent partial AV block (not quantified)
• homozygotes appear to die in utero as a result of congestive heart failure (J:18047)

homeostasis/metabolism
• at E14.5, homozygotes display a dramatic subdermal edema, that is most prominent along the back and in the folds of skin around the eye
• however, most major organ systems, including the intestine, skin, kidney and eye, appear normal

liver/biliary system
• at E12.5, homozygotes exhibit a marked reduction in hepatocyte proliferation with substantial recovery to ~60% of wild-type values noted at E14.5
• at E12.5, homozygotes display a liver mass that is ~30% of wild-type mice in the absence of morphological defects

muscle
• all homozygotes display impaired differentiation or maturation of the ventricular cardiac myocytes (J:18047)
• spongy layer of the myocardium is generally thicker (J:35363)
• 67% show attenuated trabeculae and contain an unusual, random branching pattern
• by E14.5, ventricular trabeculation is present but reduced and appears disorganized at the muscular septum
• by E14.5, homozygotes show absence of myocyte proliferation at the ventricular epicardial surface ("compact layer")
• 94% exhibit a hypoplastic compact zone of the ventricular myocardium
• 56% exhibit dysmorphic papillary muscles
• at E13.5 and E14.5, left ventricular area ejection fractions of mutant hearts average 14% vs 50% in wild-type hearts, indicating ventricular dysfunction
• at E14.5, depressed ejection fraction is related to thinned left ventricular wall and impaired shortening of the mutant myocardium

integument
• at E14.5, homozygotes display a dramatic subdermal edema, that is most prominent along the back and in the folds of skin around the eye
• however, most major organ systems, including the intestine, skin, kidney and eye, appear normal

cellular
• at E12.5, homozygotes exhibit a marked reduction in hepatocyte proliferation with substantial recovery to ~60% of wild-type values noted at E14.5




Genotype
MGI:2176444
ht2
Allelic
Composition
Rxratm1Rev/Rxra+
Genetic
Background
involves: 129S4/SvJae * C57BL/6
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Rxratm1Rev mutation (1 available); any Rxra mutation (24 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
cardiovascular system
• one heterozygote shows pulmonary artery stenosis
• 49% show trabecular defects with less organized trabecular arrangement
• intermediate thickness of compact layer compared to homozygotes and wild-type, especially prominent at E13.5 and 14.5
• 15% exhibit conotruncal defects, with severity ranging from absent conotruncal ridges (3%) to a shortened conotruncal septum (7%)
• seen in 5% of heterozygotes
• atrioventricular cushion defects range from absent fusion (3%) and hypoplasia (8%) to abnormalities of mature valvular structures
• 17% show cleft mitral valve
• 2% show mitral valve stenosis
• 8% show tricuspid valve abnormalities
• 86% show papillary muscle defects
• severe thinning of the ventricular wall is seen in both the left (2%) and right (2%) ventricles, but never simultaneously
• thin left ventricle wall is associated with mitral valve stenosis yet a normal right ventricle and semilunar valves
• thin right ventricle is associated with dysmorphic tricuspid valve yet normal left-sided and semilunar structures

muscle
• 49% show trabecular defects with less organized trabecular arrangement
• intermediate thickness of compact layer compared to homozygotes and wild-type, especially prominent at E13.5 and 14.5
• 86% show papillary muscle defects

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
congenital heart disease DOID:1682 J:35363





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last database update
08/03/2022
MGI 6.21
The Jackson Laboratory