Abstract
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. Using suppression subtractive hybridisation we found the novel zinc finger transcription factor, ZNF450 was upregulated. The single‐copy ZNF450 gene spans 15.6 kb on chromosome 10B1 and consists of seven exons, the first of which is untranslated. The open reading frame encodes a 710 reside protein. Analysis of the protein sequence reveals a highly conserved amino‐terminal BTB/POZ dimerisation domain, an AT‐hook motif, and eight C2H2 zinc fingers. Library screening identified a second mRNA isoform encoding a short protein isoform with one zinc finger. Using reverse transcriptase‐real time PCR to measure mRNA expression we found that ZNF450, Runx2/Cbfa‐1, and Sp7/osterix were induced by BMP‐2 after 4 h in C2C12 myoblast cells. Treatment of C2C12 cells with BMP‐2 causes a shift from a myoblastic to osteoblastic phenotype. ZNF450 was upregulated three to fivefold after 24 h in C3H10T1/2 cells and required 100 ng/ml BMP‐2. Expression of the 3 kb major transcript was highest in liver, testis, and kidney. However, ZNF450 mRNA was found also in a wide range of adult tissues. The consistent induction of ZNF450 by BMP‐2 after 4 h in three murine pluripotent cell lines suggests that ZNF450 may play a role in the BMP‐2 signalling pathway. © 2004 Wiley‐Liss, Inc.