FIG. 2.

(A) Viability of the offspring from crosses between MTG8^Ex2/lacZ heterozygous mice. The cumulative percent survival over the first 2 weeks after birth of 153 newborn pups representing all accounted offspring of 17 matings is shown. All five MTG8 exon 2-targeted homozygous mice surviving past day 15 were severely growth retarded. (B) ΔMidgut phenotype. An in situ view following sacrifice of a P0 homozygous mutant pup is shown. The defect extends from the distal portion of the duodenum to the rectum. The duodenal end is covered by an outgrowth of the mucosa, the rectal stump is surrounded by a prominent vascular network and the residual mesentery is hypervascularized. du, duodenum; ki, kidney; me, mesentery; re, rectum. (C) Abnormal gut structure in growth-impaired, MTG8 exon 2-targeted mice. A low-power view of hematoxylin and eosin-stained jejunal sections from mutant (−/−) and control (+/+) P29 mice is shown. Note in the mutant the reduction in gut wall thickness due primarily to disorganization of the villi; note also the dilation of the lumen.