A role of D3 expression in B-cell development. (A) Coculture experiments of D3-transduced KL cells on PA6 cells in the presence of DPAT. The number of HPCs, pro-B, pre-B, and myeloid cells yielded from huKO- or D3-transduced KL cells (□ or ■, respectively) were shown. Representative data are shown in 2 independent experiments. (B) HPCs, pro-B, and pre-B cells derived from the transduced huKO-transduced (□) or D3-tranduced KL cells (■) cultured on PA6 cells were isolated and their proliferations were determined by the proliferation assay using [³H]-thymidine in the presence or absence of DPAT (Ago + or −, respectively). Data are shown as normalized values to DPAT-free, huKO-transduced cultures in each cell population. Representative data are shown in 2 independent experiments. Error bars are ± SD. *P < .05.