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Therefore, we used only well-formed characteristic clusters (large ones) for this type of study and cut them by microknife to prepare donor cell clusters in a proper size for glass needle injection. For an estimate of the contribution of these injected cells, we used STAP cells that were generated from CD45+ cells of mice constitutively expressing GFP (C57BL/6 line with cag-gfp transgenes; F1 of C57BL/6 and 129/Sv or DBA/2 was used from the viewpoint of heterosis).
Because the number of CD45+ cells from a neonatal spleen was small, we mixed spleen cells from male and female mice for STAP cell conversion. To make germline transmission more efficient, we intercrossed chimaeras in some experiments.
