Gene expression profiles of adult murine osteoblasts and cementoblasts

Cementoblasts are cells that line the surface of the tooth root and produce a mineralized tissue known as cementum. Cementum is critical for attachment of the tooth to the adjacent periodontal ligament and has a similar biochemical composition to bone, however it differs in that it lacks vasculature and innervation, and does not undergo remodelling. It has been difficult to define markers that specifically identify cementoblasts. In order to compare the transcriptome of fully developed cementoblasts with neural crest derived (calvarial) osteoblasts in vivo, we used osteocalcin-GFP (OC-GFP) mice. Cells were isolated by digestion of calvaria (osteoblasts) or extracted molars (cementoblasts) and purified by FACS sorting for GFP positive cells before RNA extraction and microarray analysis. OC-GFP positive cells were isolated by FACS from enzymatically digested calvaria, or extracted molars from 5-7 week old OC-GFP mice. Total RNA was extracted and amplified for microarray analysis. Samples were pooled from 6-10 mice. 3 replicates are included for each sample.