Strain Detail: Col11a2-LacZ^flox-Smad7 mice

Col11a2-LacZ^flox-Smad7 mice are flox mice using conditional transgenic mouse system (Cre/loxP system) and specifically express Smad7 in chondrocytes. These mice are able to overexpress Smad7 in the any stage of chondrocytes by mating with Cre expressing transgenic mouse tissue- or stage-specifically. The transgene is inserted LacZ gene between Col11a2 (Type XI collagen alpha 2 chain gene) promoter and Smad7 cDNA, and introduced two loxP sites flanking LacZ gene. Therefore, only this mouse specifically expresses LacZ in chondrocytes, whereas in the presence of Cre, this mouse specifically expresses Smad7 in chondrocytes because of cleavage of LacZ gene.

This strain is useful for elucidation of in vivo roles of Smad7 about signal transduction of bone morphogenetic protein (BMP) which is important of osteogenesis or chondrogenesis, and expects to contribute to basic research for the therapy of motor system diseases in orthopedics. Incidentally, Smad is a protein to transduce intracellular signal of growth differentiation factor in the TGF-β super family, and it's classified receptor-regulated Smad, common Smad, antagonistic Smad. Smad7 is an antagonistic Smad.

1. Iwai T, Murai J, Yoshikawa H, Tsumaki N (2008) Smad7 Inhibits chondrocyte differentiation at multiple steps during endochondral bone formation and down-regulates p38 MAPK pathways. J Biol Chem 283:27154-27164.[PMID: 18644788]