mortality/aging
• death between E9.5 and E11.5
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cardiovascular system
• dorsal aorta and vitelline vessels were dilated
• . ectopic vasculature and hematopoeisis occurs in the amnion
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• mutant heart tubes failed to loop
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• curvature of the heart tube was irregular and appeared to bend to accommodate longitudinal growth
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• severely delayed in most surviving embryos
(J:53293)
|
digestive/alimentary system
• some embryos exhibited a vestigial foregut and hindgut
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embryo
• extreme anterior body curvature with a close head-to-tail apposition
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• in the most severely affected embryos, turning never initiated and in older surviving embryos, turning was not complete or occurred in the opposite direction
(J:53293)
• 53% of embryos failed to initiate turning and the remainder failed to complete turning
(J:60975)
|
• expression patterns of left-right axis determination genes was perturbed in addition to the heart looping and embryonic turning defects, suggesting that Smad5 is required for normal left-right axis determination
|
• posterior region of embryo extended proximally far above the level of the head folds
• posterior regions were fragile and poorly developed in older surviving embryos
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• underdeveloped appearance
|
• elayed cephalic neural tube closure; absent in some cases
• may be a secondary effect of heart defects since expression of neural markers was not altered between mutant embryos and controls
|
• poorly elongated allantois with an enlarged base
|
• at E9.5, hemorrhagic structures were observed
• ectopic vasculature and hematopoeisis occurs in the amnion
• at E8.0-E8.5, some embryos showed abnormal amnion morphology; others exhibited cell aggregates at later stages that appeared to be derived from extraembryonic mesoderm
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pale yolk sac
(
J:53293
)
• yolk sac had anemic appearance
|
• yolk sacs lacked networks of branching vitelline vessels, but did contain a primitive plexus
|
growth/size/body
• heart not enclosed by the body wall, remaining exteriorized
• in older embryos, the posterior body wall remains open (the lateral body wall rarely closed around the ventral midgut region)
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homeostasis/metabolism
reproductive system
• reduced number of primordial germ cells (PGCs)
• on average, 8 PGCs were detected in embyros with 0 to 5 somites (age matched wild-type mice had 65 PGCs)
• PGCs were undetected in ~20% of mice
• ectopic PGCs were observed in the amnion of some mice
|
nervous system
• elayed cephalic neural tube closure; absent in some cases
• may be a secondary effect of heart defects since expression of neural markers was not altered between mutant embryos and controls
|
• in severely affected embryos, development of the prosencephalon and the optic sulcus was delayed
|
exencephaly
(
J:53293
)
• in severely affected embryos, due to failure of neural tube closure
|
craniofacial
• underdeveloped appearance
|
cellular
• reduced number of primordial germ cells (PGCs)
• on average, 8 PGCs were detected in embyros with 0 to 5 somites (age matched wild-type mice had 65 PGCs)
• PGCs were undetected in ~20% of mice
• ectopic PGCs were observed in the amnion of some mice
|