(A) Northern blot analysis of poly A+ RNA extracted from normal mouse tissues. The blots were probed with a D3 specific probe (top) and reprobed with human β-actin (bottom). (B) Northern blot analysis of RNA extracted from BMC, lineage-depleted BMC (Lin⁻), and Lin⁻ cells purified by flow cytometry for expression of c-Kit (Lin⁻c-Kit⁺). The blots were probed with the D3 specific probe (top) and equal loading of samples was verified by ethidium bromide staining of rRNA (bottom). (C) RT-PCR analysis of D3 expression (left) in Lin⁻ c-Kit⁺ Sca-1⁺ BMC cultured 0, 3, and 7 days in IL-3/SCF. Amplification of actin from each cDNA sample is shown (right).