Bone Analysis of T-Cell Leukaemia Translocation-Associated Gene (TCTA) Transgenic Mice and Conditional Knockout Mice: Possibility that TCTA Protein Expressed on Osteoclasts Plays a Role as a Novel Coupling Factor In Vivo

T-cell leukemia translocation-associated gene (TCTA) protein is expressed ubiquitously in normal human tissues. However, its function has not been clarified. In 2009, we demonstrated that TCTA protein play an important role in human osteoclastogenesis and pit formation of mature human osteoclasts inducing the fusion process of osteoclastogenesis in vitro. In the current study, to clarify the role of TCTA protein in vivo, we generated TCTA gene transgenic, both systemic and osteoclast-specific, mice and osteoclast-specific conditional knockout mice and then analyzed their bones. Surprisingly, in the conditional knockout mice, bone volume decreased despite inhibited osteoclastogenesis. According to these findings, we speculated that TCTA protein expressed on osteoclasts plays a role as a E»coupling factorE¼ in vivo.