All Phenotypes Has2<tm1Jam> MGI Mouse

embryonic lethality during organogenesis, complete penetrance ( J:63748 )

• homozygotes die during midgestation between E.9.5 and E10

• partial resorptions are first observed at E11.5

abnormal blood vessel morphology ( J:63748 )

• at E9.5, homozygotes show absence of an organized vascular network relative to wild-type

absent vitelline blood vessels ( J:63748 )

• mutant embryos contain scant numbers of red blood cells and lack vessels in the yolk sac

abnormal cardiac epithelial to mesenchymal transition ( J:63748 )

• in an explant system, homozygotes show absent cell migration and epithelium-to-mesenchyme transformation in the atrioventricular (AV) canal and outflow tract; transformation is rescued by Has2 cDNA or the addition of purified HA

abnormal cardiac outflow tract development ( J:63748 )

• mutant hearts show partial or complete obstruction of the outflow tract

abnormal heart morphology ( J:63748 )

• mutant hearts show significant compaction of the extracellular space

• homozygotes lack alcian blue-staining glycosaminoglycans and HA in cardiac jelly; in contrast, collagen I, fibronectin, laminin, and versican are present

absent trabeculae carneae ( J:63748 )

• the mutant myocardium lacks trabeculae even though the ventricular wall is several cell layers thick

absent cardiac jelly ( J:63748 )

• mutant hearts display absence of cardiac jelly

absent atrioventricular cushions ( J:63748 )

• mutant hearts display absence of cardiac jelly and cushions, despite a characteristic constriction at the atrioventricular (AV) region

heart atrium hypoplasia ( J:63748 )

• at E9.5, the mutant atrium is smaller than wild-type

decreased heart right ventricle size ( J:63748 )

• at E9.5, homozygotes dispaly a significant reduction of the right ventricle

pericardial edema ( J:63748 )

• mutant hearts often display significant pericardial swelling

irregular heartbeat ( J:63748 )

• hearts of viable homozygotes beat with a distinctive to-and-fro motion of red blood cells

absent vitelline blood vessels ( J:63748 )

• mutant embryos contain scant numbers of red blood cells and lack vessels in the yolk sac

incomplete embryo turning ( J:63748 )

• at E9.5, some homozygous mutant embryos have failed to turn

embryonic growth retardation ( J:63748 )

• occasionally, viable embryos are detected at E10.5 with beating hearts and significant growth retardation

abnormal embryonic tissue morphology ( J:63748 )

• at E9.5, homozygotes show posterior defects

abnormal head mesenchyme morphology ( J:63748 )

• at E9.5, homozygotes show cephalic mesenchyme abnormalities

abnormal somite shape ( J:63748 )

• at E9.5, somites are present but appear distorted; other structures including the first pharyngeal pouch and otic placodes are also present

abnormal visceral yolk sac morphology ( J:63748 )

• mutant yolk sacs have a punctate appearance

abnormal extraembryonic endoderm formation ( J:63748 )

• in homozygotes, the visceral endoderm and mesoderm that form the yolk sac fail to fuse except at discrete foci; red blood cells are free within this space