The Sp7 gene is a C2H2-type zinc finger transcription factor of the SP gene family and
putative master regulator of bone cell differentiation. In this strain, Cre recombinase
expression is under the control of Sp7 promoter. When crossed with a strain containing
a loxP site-flanked sequence of interest, Cre-mediated recombination results in deletion
of the flanked sequence in Sp7 expressing cells.

An F2A-iCre sequence cassette was placed between the coding sequence of exon 2 and 3' UTR of the Sp7 gene in C57BL/6 ES cells. This strain was maintained on a C57BL/6 genetic background.

qPCR, Western blot, and Immunofluorescence analyses showed that Fam20c knockout resulted in a decreased expression of Calpastatin in OB Fam20cKO cells (Fig. A, B, E), whereas accompanied by a decreased phosphorylated expression level of Calpastatin (Fig. C). These were consistent with the results of proteomics and phosphoproteomics. Furthermore, Fam20cdeficient osteoblasts displayed a diminished expression of Calpain 1 and Calpain 2 (Fig. A, B, E) and attenuation of Calpain activity (Fig. D). (source: Liuetal. Journal of Translational Medicine (2023) 21:417)