Phenotypes associated with this allele

• Allele Symbol: Tbx20^tm1.1Sev
• Allele Name: targeted mutation 1.1, Sylvia Evans
• Allele ID: MGI:3579849
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Tbx20^tm1.1Sev/Tbx20^tm1.1Sev	involves: 129S6/SvEvTac * C57BL/6	MGI:3579852
cn2	Tbx20^tm1Sev/Tbx20^tm1.1Sev Nfatc1^tm1.1(cre)Bz/Nfatc1^+	involves: 129S1/Sv * 129S6/SvEvTac * 129X1/SvJ * Black Swiss	MGI:5524038

Genotype
MGI:3579852

hm1

• Allelic Composition: Tbx20^tm1.1Sev/Tbx20^tm1.1Sev
• Genetic Background: involves: 129S6/SvEvTac * C57BL/6

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

mortality/aging

embryonic lethality during organogenesis, complete penetrance ( J:98516 )

• death at E10.5

cardiovascular system

failure of heart looping ( J:98516 )

• looping is blocked

abnormal heart tube morphology ( J:98516 )

• at E9.5 the heart is unlooped, hourglass shaped, and severely hypoplastic

heart hypoplasia ( J:98516 )

abnormal fetal cardiomyocyte proliferation ( J:98516 )

• decreased proliferation is seen atE8.0 and E8.5; however, apoptosis is not increased

embryo

embryonic growth arrest ( J:98516 )

• growth arrest at E9.0

muscle

abnormal fetal cardiomyocyte proliferation ( J:98516 )

• decreased proliferation is seen atE8.0 and E8.5; however, apoptosis is not increased

cellular

abnormal fetal cardiomyocyte proliferation ( J:98516 )

• decreased proliferation is seen atE8.0 and E8.5; however, apoptosis is not increased

Genotype
MGI:5524038

cn2

• Allelic Composition: Tbx20^tm1Sev/Tbx20^tm1.1Sev; Nfatc1^tm1.1(cre)Bz/Nfatc1⁺
• Genetic Background: involves: 129S1/Sv * 129S6/SvEvTac * 129X1/SvJ * Black Swiss

mortality/aging

lethality throughout fetal growth and development, complete penetrance ( J:198628 )

• embryos die between E14.5 and E16.5

cardiovascular system

decreased atrioventricular cushion size ( J:198628 )

• smaller in size

• pulmonary and aortic valve cushions are normal in size at E12.5

abnormal heart valve morphology ( J:198628 )

• all heart valves are similarly affected at E14.5

• heart valve leaflets are shorter and blunt relative to controls

• endocardial cell proliferation in all valves is much reduced while mesenchymal cell proliferation is unchanged

• little apoptosis

small atrioventricular valve ( J:198628 )

• mitral and tricuspid valves are much shorter than controls

small semilunar valve ( J:198628 )

• semilunar valves are 66 or 69% of the control length

abnormal cardiovascular system physiology ( J:198628 )

hemorrhage ( J:198628 )

• peripheral hemorrhage in most embryos at E15.5

aortic valve regurgitation ( J:198628 )

• significant at E14.5