Genome-wide analyses of gene expression during mouse endochondral ossification.
BACKGROUND
Endochondral ossification is a complex process involving a series of events that are initiated by the establishment of a chondrogenic template and culminate in its replacement through the coordinated activity of osteoblasts, osteoclasts and endothelial cells. Comprehensive analyses of in vivo gene expression profiles during these processes are essential to obtain a complete understanding of the regulatory mechanisms involved.


RESULTS
To address these issues, we completed a microarray screen of three zones derived from manually segmented embryonic mouse tibiae. Classification of genes differentially expressed between each respective zone, functional categorization as well as characterization of gene expression patterns, cytogenetic loci, signaling pathways and functional motifs both confirmed reported data and provided novel insights into endochondral ossification. Parallel comparisons of the microdissected tibiae data set with our previously completed micromass culture screen further corroborated the suitability of micromass cultures for modeling gene expression in chondrocyte development. The micromass culture system demonstrated striking similarities to the in vivo microdissected tibiae screen; however, the micromass system was unable to accurately distinguish gene expression differences in the hypertrophic and mineralized zones of the tibia.


CONCLUSIONS
These studies allow us to better understand gene expression patterns in the growth plate and endochondral bones and provide an important technical resource for comparison of gene expression in diseased or experimentally-manipulated cartilages. Ultimately, this work will help to define the genomic context in which genes are expressed in long bones and to understand physiological and pathological ossification.
James
Claudine G
CG
CIHR Group in Skeletal Development and Remodelling, Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.
Stanton
Lee-Anne
LA
Agoston
Hanga
H
Ulici
Veronica
V
Underhill
T Michael
TM
Beier
Frank
F
D000818:Animals; D001483:Base Sequence; D001846:Bone Development; D019902:Chondrocytes / Q000378:metabolism / Q000502:physiology*; D017931:DNA Primers; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D016678:Genome; D006132:Growth Plate / Q000196:embryology*; D051379:Mice; D014158:Transcription, Genetic
D017931:DNA Primers