Analysis Tools
mortality/aging
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• all homozygotes die within a few days after birth
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digestive/alimentary system
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• mutant intestines are of normal length and show no overt abnormalities; however, the loops of the small intestine are positioned slightly differently in the abdomen relative to wild-type
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endocrine/exocrine glands
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• at E10, the mutant dorsal pancreatic epithelium forms a bud but then becomes growth arrested and fails to lobulate
• at E11 and E12, the dorsal bud is significantly smaller than wild-type; the remaining, growth-arrested bud remains unbranched
• at E10-E12, the mutant ventral pancreatic bud appears to be absent
• although the mutant pancreatic epithelium is growth-arrested, the dorsal pancreatic mesenchyme grows and develops normally, with a morphologically normal, bud-like shape found at its normal position
• notably, the mutant mesenchyme is functionally active and able to promote morphogenesis and differentiation of pancreatic epithelium when recombined in vitro; in contrast, mutant pancreatic epithelium cannot be rescued by adding wild-type mesenchyme
• at E13.5, the mutant dorsal pancreatic mesenchyme is present as a "hollow pocket" that can be dissected away from the stomach and duodenum; in wild-type E13-E14 embryos, this mesenchymal pocket is filled by pancreatic epithelium
• at E10, early glucagon cells are present but are unable to proliferate and/or differentiate; a few early insulin cells are present at E10, but are no longer detectable at E13, in the absence of increased apoptosis
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• homozygotes completely lack a pancreas; no pancreatic tissue is present in E15.5 embryos or neonates
• notably, the duodenum (from which the pancreas develops) has a normal C-shaped form; no ectopic expression of insulin and pancreatic amylase is detected in the developing duodenum
• the pancreatic duct is missing; however, the common bile duct is present, indicating that apart from the lack of pancreas, the duodenal tract is normally developed
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growth/size/body
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• homozygotes appear morphologically normal but are slightly smaller than wild-type and heterozygous littermates: on average, ~80% for newborn pups and ~60% for 2-day-old pups
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homeostasis/metabolism
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• pups that are able to feed and live for more than 2 days exhibit elevated glucose levels, suggesting that the cause of death is partly due to insulin deficiency
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immune system
| N |
• mutant spleens are of normal weight and show no apparent abnormalities relative to wild-type
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liver/biliary system
| N |
• mutant livers are of normal weight and show no apparent abnormalities relative to wild-type
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