Analysis Tools
mortality/aging
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• nearly all homozygotes that survive past the first 2 days are significantly smaller and usually die before reaching puberty
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• ~25% of homozygotes die within one day after birth due to a massive defect in the gastrointestinal tract
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• an additional ~35% of homozygotes die within the second day after birth
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growth/size/body
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• homozygotes surviving past P15 are 30% to 50% the size of wild-type littermates in weight, but appear well proportioned and active, except in extreme cases
• although a few surviving homozygotes gradually recover with age after puberty, they exhibit below-average weight
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omphalocele
(
J:70590
)
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• at E17.5, homozygous mutant embryos display persistence of the umbilical hernia, normally disappearing by E16.5 in wild-type controls
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• a number of homozygotes that survive past the first 48 hrs show a progressive growth impairment over the next 2 weeks of life
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digestive/alimentary system
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• at P0-P1, intraparietal and intraluminal hemorrhages are occasionally observed over the sigma-rectum
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absent midgut
(
J:70590
)
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• at P0-P1, ~25% of homozygotes show an absence of the midgut, with the defect extending from the distal portion of the duodenum to the rectum
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• at P0-P1, the intestinal wall thickness is reduced due primarily to disorganization of the villi while the intestinal lumen appears dilated
• the remaining duodenal and rectal stumps are loosely held together by a short, fibrous, highly vascularized membrane in place of the mesentery
• although no differences in gut morphogenesis are noted up to E15.5, the umbilical hernia appears to be somewhat smaller than in controls and the complexity of the midgut loops is reduced at E17.5
• however, no differences in gut cell differentiation or proliferation are observed and levels of factors known to be involved in gut morphogenesis appear unaffected
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• growth-impaired homozygotes display a thinner intestinal wall, primarily due to a reduction in the length of the villi at the level of the jejunum
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• at P0-P1, the residual distal (rectal) stump is blind ended and surrounded by a prominent vascular network
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• at P0-P1, the residual proximal (duodenal) stump is pervious and covered by an outgrowth of the mucosa, with villi projecting into the peritoneal cavity
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• at the level of the jejunum, mutant villi are reduced in length and appear highly disorganized, thicker, and fewer in numbers relative to wild-type; however, shorter villi are not the result of reduced epithelial stem cell activity
• a less extensive disruption of villi than that observed postnatally is already evident at E17.5
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behavior/neurological
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• at P0-P1, a fraction of homozygous mutant pups lack milk in their stomachs
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cardiovascular system
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• at P0-P1, intraparietal and intraluminal hemorrhages are occasionally observed over the sigma-rectum
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reproductive system
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• male homozygotes surviving into adulthood fail to sire offspring, despite successful mating
• in contrast, surviving female homozygotes are fertile, despite their size reduction
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integument
