Human donor contribution in developing murine embryos after injection of purified human CD34⁺CD38⁻ cells into murine blastocysts.

(A) (B) Detection of human donor contribution in embryonic and adult tissues by means of 17αmod PCR on genomic DNA from developing E11.5 embryos (panel A) and an adult at 5 months of age (panel B) following blastocyst injection of CD34⁺CD38⁻ cells (panel A) and CD34⁺ cells (panel B). Graded numbers of human cells diluted into 10⁵ murine (mu) splenocytes were used for quantification of the PCR products. PCR specific for murine myogenin was used for normalization of genomic DNA.2 (C) Photograph of a human colony (25 × magnification) and 17αmod PCR on genomic DNA extracted from single colonies after 10 days of culture. (D) Human globin–specific RT-PCR on total RNA isolated from CB fractions and from chimeric embryonic tissues. As positive controls, RT-PCR was done on a mixture (1/500) of total RNA prepared from unfractionated cord blood and murine fetal liver samples. Abbreviations: P, placenta; Y, yolk sac; L, fetal liver; H, head; B, embryonic blood; T, thymus; BM, bone marrow; Sp. co., spinal cord; N. isch., nervus ischiadicus; hu DNA, human genomic DNA; mu DNA, murine genomic DNA; unfr. CB, unfractionated CB; MNCs, mononuclear cells. Autoradiograms of Southern blots are shown.