The bcl-2 knockout mouse exhibits marked changes in osteoblast phenotype and collagen deposition in bone as well as a mild growth plate phenotype.
Histological examination of long bones from 1-day-old bcl-2 knockout and age-matched control mice revealed no obvious differences in length of bone, growth plate architecture or stage of endochondral ossification. In 35-day-old bcl-2 knockout mice that are growth retarded or 'dwarfed'. the proliferative zone of the growth plate appeared slightly thinner and the secondary centres of ossification less well developed than their age-matched wild-type controls. The most marked histological effects of bcl-2 ablation were on osteoblasts and bone. 35-day-old knockout mouse bones exhibited far greater numbers of osteoblasts than controls and the osteoblasts had a cuboidal phenotype in comparison with the normal flattened cell appearance. In addition, the collagen deposited by the osteoblasts in the bcl-2 knockout mouse bone was disorganized in comparison with control tissue and had a pseudo-woven appearance. The results suggest an important role for Bcl-2 in controlling osteoblast phenotype and bone deposition in vivo.
Boot-Handford
R P
RP
Wellcome Trust Centre of Cell-Matrix Research, School of Biological Sciences, University of Manchester, UK. ray.boot-handford@man.ac.uk
Michaelidis
T M
TM
Hillarby
M C
MC
Zambelli
A
A
Denton
J
J
Hoyland
J A
JA
Freemont
A J
AJ
Grant
M E
ME
Wallis
G A
GA
D000818:Animals; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology*; D003094:Collagen / Q000378:metabolism*; D004392:Dwarfism / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019254:Genes, bcl-2; D006132:Growth Plate / Q000473:pathology; D007124:Immunoenzyme Techniques; D051379:Mice; D018345:Mice, Knockout; D010006:Osteoblasts / Q000473:pathology* / Q000502:physiology; D010641:Phenotype
D003094:Collagen