Lineage tracing using matrilin-1 gene expression reveals that articular chondrocytes exist as the joint interzone forms.

We have developed a mouse in which the Cre recombinase gene has been targeted to exon 1 of the matrilin-1 gene (Matn1) to investigate the origins of articular chondrocytes and the development of the knee joint. Analysis of joints from offspring of Matn1-Cre/R26R crosses demonstrated that articular chondrocytes are derived from cells that have never expressed matrilin-1 whereas the remainder of the chondrocytes in the cartilage anlagen expresses matrilin-1. A band of chondrocytes adjacent to the developing interzone in the E13.

Bone morphogenetic protein-2 induces expression of murine zinc finger transcription factor ZNF450.

The bone morphogenetic protein-2 (BMP-2) is a potent secreted factor that promotes osteoblast differentiation during development. Exposure to BMP-2 is sufficient to cause a lasting change in cell fate presumably by activating specific target genes. To identify genes downstream of BMP-2 we treated the murine pluripotent embryonic cell line, C3H10T1/2 that can be induced to form an osteoblastic phenotype, with 100 ng/ml BMP-2 for 24 h.