Expression of WT tcirg1 is up-regulated during osteoclast differentiation, while vector-mediated expression is down-regulated. Quantitative RT-PCR was performed on cDNA from freshly isolated BM cells (0 days) harvested from WT and oc/oc+tcirg1 mice (GFP⁺ cells) and after 6 days of culture with M-CSF and RANKL to determine the level of tcirg1 expression. Tcirg1 PCR values were normalized against the corresponding HPRT value giving a relative intensity value for comparison of different samples. Expression levels are compared to the tcirg1 vector GP+E86 producer cell line and the GFP vector GP+E86 producer cell line.