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Fig. 2. Genes characteristically expressed during chondrocyte hypertrophy and
calcification were found to be differentially expressed during ES cell
differentiation in vitro. Genes encoding extracellular matrix proteins of
cartilage tissue such as collagen II (A), collagen X (B), osteocalcin (C) and
the osteoblast-specific transcription factor Cbfa-1 (D) were
expressed in EBs from different cultivation stages from 2 (5+2 d) up to 30
days (5+30 d) after plating as demonstrated by RT-PCR. The primers used to
amplify collagen II transcripts detected two splice variants (A), the
juvenile variant A and the adult variant B. The
transcriptional levels relative to those of the house-keeping gene
HPRT are presented. Mean values±s.e.m. derived from
independent experiments (n=4) are shown.