Synergistic role of Igf2 and Dlk1 in fetal liver development and Hematopoiesis in bi-maternal mice
Synergistic role of Igf2 and Dlk1 in fetal liver development and Hematopoiesis in bi-maternal mice
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DOI：
10.1262/jrd.19146
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发表时间：
2008-06-01
影响因子：
1.8
通讯作者：
Kono, Tomohiro
中科院分区：
文献类型：
--
作者：
Wu, Qiong;Kawahara, Manabu;Kono, Tomohiro
小鼠双母体胚胎 (BME) 包含来自非生长 (ng) 和完全生长 (fg) 卵母细胞的两组单倍体基因组，发育至胚胎日 (E) 13.5。然而，由于父系表达的印记基因 Igf2 和 Dlk1 的抑制，ng/fg BME 从未发育超过 E13.5。本研究旨在解决胎儿造血障碍是否与 BME 发育受限有关的问题。 FACS分析显示ng(wt)/fg BME的肝脏中未成熟c-kit(+)/ter119(-)造血细胞数量增加，而成熟c-kit(-)/ter119(+)造血细胞数量减少。这一发现得到了组织学观察的支持。定量基因表达分析显示肝脏中 Igf2 和 Dlk1 的表达受到抑制。为了了解 7 号和 12 号染色体上的父系甲基化印记基因，特别是 Igf2 和 Dlk1，在胎儿肝脏造血中的作用，我们使用 ng 卵母细胞构建了 ng(Delta ch7)/fg、ng(Delta ch12)/fg 和 ng(Delta Double)/fg BME，该卵母细胞在远端 7 号和/或 12 号染色体上删除了差异甲基化区域。 ch7)/fg、ng(Delta ch12)/fg 和 ng(Delta Double)/fg BME 分别表达 Igf2、Dlk1 或两者，并且这些胚胎发育至具有特定表型的足月； ng(Delta ch7)/fg 和 ng(Delta ch12)/fg BME 发育至足月时伴有严重的生长迟缓，ng(Delta Double)/fg BME 可以存活成为正常雌性成虫。通过诱导 Igf2 和 Dlk1 表达，ng(Delta ch7)/fg、ng(Delta ch12)/fg 和 ng(Delta Double)/fg BME 肝脏中成熟和未成熟造血细胞的比例显着恢复，特别是在 ng(Delta Double)/fg BME 中，造血正常发生，相关基因适当表达。这些数据表明 Igf2 和 Dlk1 的不当表达与胎儿造血功能受损有关。
Mouse bi-maternal embryos (BMEs) that contain two haploid sets of genomes from non-growing (ng) and fully-grown (fg) oocytes develop to embryonic day (E) 13.5. However, the ng/fg BMEs never develop beyond E13.5 because of repression of the paternally expressed imprinted genes, Igf2 and Dlk1. The present study was conducted to address the issue of whether fetal hematopoietic disorder is involved in the restricted development of BMEs. FACS analysis revealed that the livers of ng(wt)/fg BMEs contained increased numbers of immature c-kit(+)/ter119(-) hematopoietic cells, were while the numbers of mature c-kit(-)/ter119(+) hematopoietic cells were decreased. This finding was supported by histological observations. Quantitative gene expression analysis revealed that Igf2 and Dlk1 expression was repressed in the liver. To understand the role of paternally-methylated imprinted genes on chromosomes 7 and 12, particularly Igf2 and Dlk1, in fetal liver hematopoiesis, we constructed ng(Delta ch7)/fg, ng(Delta ch12)/fg and ng(Delta Double)/fg BMEs using ng oocytes harboring deletion of differentially methylated regions at distal chromosomes 7 and/or 12. The ng(Delta ch7)/fg, ng(Delta ch12)/fg and ng(Delta Double)/fg BMEs, respectively, express Igf2, Dlk1 and both, and these embryos developed to term with specific phenotypes; the ng(Delta ch7)/fg and ng(Delta ch12)/fg BMEs develop to term with severe growth retardation, and the ng(Delta Double)/fg BMEs can survive to become normal female adults. By inducing Igf2 and Dlk1 expression, the proportions of mature and immature hematopoietic cells in the livers of the ng(Delta ch7)/fg, ng(Delta ch12)/fg and ng(Delta Double)/fg BMEs were considerably restored, and particularly in the ng(Delta Double)/fg BMEs, hematopoiesis occurred normally with appropriate expressions of the related genes. These data suggest that inappropriate expression of Igf2 and Dlk1 is involved in impaired fetal hematopoiesis.