![Figure 4. Megakaryocyte maturation is inefficient in pIpC-treated Runx1-excised mice. BM from representative (A) Runx1F/F and (B) Runx1F/F—Tg(Mx1-Cre) mice 143 days after pIpC injection shows an absence of normal megakaryocytes in Runx1-excised mice (hematoxylin and eosin [H&E] staining; original magnification, × 600). (C) BM from representative Runx1F/F—Tg(Mx1-Cre) recipient mice 98 days after transplantation (H&E; original magnification, × 600). (A-C) Yellow arrows indicate representative megakaryocytes. Red and green arrowheads indicate representative erythroid and myeloid elements, respectively. Sections demonstrate a notable absence of megakaryocytes and an increased ratio of maturing myeloid-to-erythroid forms in Runx1-excised versus nonexcised marrows. (D) Histograms depicting number of cultured Runx1F/F and Runx1F/F—Tg (Mx1-Cre) bone marrow cells stained with propidium iodide to show ploidy. Colors indicate CD41 gates: green, CD41+; red, CD41–. (E, left) Plotted are mean ± SD numbers of acetylcholinesterase-positive colonies per 5 × 104 BM cells plated from pIpC-treated Runx1F/F (□) and Runx1F/F—Tg(Mx1-Cre) (▪) mice. Results shown are for 3 experiments performed in quadruplicate. 1 and 3, fresh marrow; 2, previously frozen marrow. (Right) Plotted is the average fold increase for Runx1F/F—Tg(Mx1-Cre) (▪) relative to Runx1F/F (□) in the 3 experiments (P ≤ .034). Representative megakaryocyte colonies from (F) Runx1F/F and (G) Runx1F/F—Tg(Mx1-Cre) mice show acetylcholinesterase staining (brown) of megakaryocytic cells (original magnification, × 100).](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/106/2/10.1182_blood-2004-08-3280/6/zh80140581270004.jpeg?Expires=1724293248&Signature=SjZfmz4HsGOr795d2cIY4QBfyA20njw0hHv9EhcC3o0gZtxwRekfAOKojb88REIKjVcIBqHpRXZHj-vpfLzQJC~30yV0i~0-5SeRYs31rmQ8JYyfs85I3l5dQdeKmbVwq-aPBmezB~RAyPSYJywGlPwO2fq~UmfnkZ~6Ed5qQ7YwfwEIksB1MFI--CHhPfhqW~fHSnoiW9sXqXzlh1SHSajcrKN~kqgUkF0pT51SGvO2VKBTN53HG33MyOa17CiDnvC2AE2nB1ebcbv~S65fGOBBSegcEnFlz7R0k34Zz-tIxP3-Th-vJvgsfTQMZPVUk88JIohDbnC4QZffqyWdjA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Megakaryocyte maturation is inefficient in pIpC-treated Runx1-excised mice. BM from representative (A) Runx1F/F and (B) Runx1F/F—Tg(Mx1-Cre) mice 143 days after pIpC injection shows an absence of normal megakaryocytes in Runx1-excised mice (hematoxylin and eosin [H&E] staining; original magnification, × 600). (C) BM from representative Runx1F/F—Tg(Mx1-Cre) recipient mice 98 days after transplantation (H&E; original magnification, × 600). (A-C) Yellow arrows indicate representative megakaryocytes. Red and green arrowheads indicate representative erythroid and myeloid elements, respectively. Sections demonstrate a notable absence of megakaryocytes and an increased ratio of maturing myeloid-to-erythroid forms in Runx1-excised versus nonexcised marrows. (D) Histograms depicting number of cultured Runx1F/F and Runx1F/F—Tg (Mx1-Cre) bone marrow cells stained with propidium iodide to show ploidy. Colors indicate CD41 gates: green, CD41+; red, CD41–. (E, left) Plotted are mean ± SD numbers of acetylcholinesterase-positive colonies per 5 × 104 BM cells plated from pIpC-treated Runx1F/F (□) and Runx1F/F—Tg(Mx1-Cre) (▪) mice. Results shown are for 3 experiments performed in quadruplicate. 1 and 3, fresh marrow; 2, previously frozen marrow. (Right) Plotted is the average fold increase for Runx1F/F—Tg(Mx1-Cre) (▪) relative to Runx1F/F (□) in the 3 experiments (P ≤ .034). Representative megakaryocyte colonies from (F) Runx1F/F and (G) Runx1F/F—Tg(Mx1-Cre) mice show acetylcholinesterase staining (brown) of megakaryocytic cells (original magnification, × 100).
