A human CD34 transgene containing 18 kb of 5′ upstream and 43 kb of 3′ downstream sequences (PAC54A19) expresses RNA in a manner similar to the endogenous murine CD34 gene in transgenic mice.

(A) Northern blot analysis of 10 μg RNA isolated from tissues of nontransgenic (−) and transgenic (+) littermates. The same blot was hybridized with a probe specific for human CD34 (3′ untranslated region), for murine CD34 (3′ untranslated region), and subsequently to GAPDH as described in “Materials and methods.” A similar pattern of expression was observed in all 4 founder lines derived from PAC54A19, including those digested with PvuI, as well as in the founder lines of the larger (−48, −31, and −23 kb) constructs shown in Figure 1. (B) Human CD34 RNA expression in transgenic mice is copy number–dependent. The expression of human CD34 RNA in heart from the 4 independent PAC54A19 founders (○) was determined by ImageQuant (Molecular Dynamics, Sunnyvale, CA) and standardized to GAPDH expression. The gene copy number was determined by Southern blot analysis. ● represents one transgenic founder containing 141 kb of human CD34 genomic DNA (PAC88L2), as previously reported.19