mortality/aging
• no mice survive to weaning
|
• about half are found dead at birth or die within a few hours of birth
|
• about half are found dead at birth or die within a few hours of birth
|
growth/size/body
• mice that survive past bthe perinatal period become severely runted by 2 weeks of age
|
skeleton
• C8 has rib anlagen that does not attach to the sternum or to the first pair of thoracic ribs
|
• lack a pair of floating ribs
|
• in the region of C3 to C8 the spinal column is compressed causing an S shaped deformation of the neck and forward tilt of the head
|
• most mice are missing a vertebra, associated with loss of a pair of floating ribs
|
• S shaped deformation of the neck and forward tilt of the head
|
• C3 looks more like C2 than C4 with a round rather than oval cross sectional shape
|
• in all cases C1 is about twice as tall as in wild-type controls
• C1 has the appearance of 2 partially fused vertebrae
|
• malformations of C2 are sometimes seen
• in a few cases C2 looks like 2 partially fused vertebrae
|
• in some cases C2 and C3 appear partially fused
|
• anterior homeotic transformation from C3 through T13
• however, lumbar and caudal vertebrae appear similar to controls
|
• most mice have an extra cervical vertebra compensating for loss of a thoracic vertebra
• the spinous process usually found of T2 is seen on T3
|
• in newborns, sternums consist mainly of bone rather than bone and cartilage
|
embryo
• in situ hybridization analysis of E9.5 mutant embryos revealed a posterior shift in the anterior expression limits of Hoxd4, corresponding to approximately one rhombomere, indicating altered embryo patterning
|
hematopoietic system
N |
• mutant neonates displayed normal hematopoiesis, as shown by histology and flow cytometry
|