Targeted histone demethylation improves somatic cell reprogramming into cloned blastocysts but not postimplantation bovine concepti
Targeted histone demethylation improves somatic cell reprogramming into cloned blastocysts but not postimplantation bovine concepti
复制标题
靶向组蛋白去甲基化可改善体细胞重编程为克隆囊胚，但不能改善植入后牛受孕
DOI：
10.1093/biolre/ioaa053
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发表时间：
2020-07-01
影响因子：
3.6
通讯作者：
Oback, Bjorn
中科院分区：
文献类型：
--
作者：
Meng, Fanli;Stamms, Kathrin;Oback, Bjorn
供体核中表观遗传标记的正确重编程是体细胞移植（SCT）成功克隆的先决条件。在一些哺乳动物物种中，抑制性组蛋白 (H) 赖氨酸 (K) 三甲基化 (me3) 标记，特别是 H3K9me3，形成体细胞重编程为多能性和全能性的主要障碍。我们对牛胚胎成纤维细胞 (BEF) 进行了改造，用于多西环素诱导表达具有生物活性的截短形式的鼠 Kdm4b，这是一种去除 H3K9me3 和 H3K36me3 标记的去甲基化酶。与未诱导的对照相比，诱导 Kdm4b 后，H3K9me3 和 H3K36me3 水平分别降低约 3 倍和 5 倍。此前，供体细胞静止与牛体细胞三甲基化水平降低和克隆效率提高有关。与未诱导、非饥饿的对照成纤维细胞相比，同时诱导 Kdm4b 表达（通过强力霉素）和静止（通过血清饥饿）进一步降低了 H3K9me3 和 H3K36me3 的整体水平，分别达 18 倍和 35 倍。 SCT 后，与未诱导的供体细胞相比，Kdm4b-BEF 能更好地重新编程为克隆囊胚。然而，去三甲基化的供体和胚胎培养期间持续的 Kdm4b 诱导并没有增加囊胚从植入到成年存活的发育率。总之，在供体细胞中过度表达 Kdm4b 仅改善了它们进入植入前早期阶段的重编程，这突出表明需要替代实验方法来可靠地提高牛的体细胞克隆效率。
Correct reprogramming of epigenetic marks in the donor nucleus is a prerequisite for successful cloning by somatic cell transfer (SCT). In several mammalian species, repressive histone (H) lysine (K) trimethylation (me3) marks, in particular H3K9me3, form a major barrier to somatic cell reprogramming into pluripotency and totipotency. We engineered bovine embryonic fibroblasts (BEFs) for the doxycycline-inducible expression of a biologically active, truncated form of murine Kdm4b, a demethylase that removes H3K9me3 and H3K36me3 marks. Upon inducing Kdm4b, H3K9me3 and H3K36me3 levels were reduced about 3-fold and 5-fold, respectively, compared with noninduced controls. Donor cell quiescence has been previously associated with reduced somatic trimethylation levels and increased cloning efficiency in cattle. Simultaneously inducing Kdm4b expression (via doxycycline) and quiescence (via serum starvation) further reduced global H3K9me3 and H3K36me3 levels by a total of 18-fold and 35-fold, respectively, compared with noninduced, nonstarved control fibroblasts. Following SCT, Kdm4b-BEFs reprogrammed significantly better into cloned blastocysts than noninduced donor cells. However, detrimethylated donors and sustained Kdm4b-induction during embryo culture did not increase the rates of postblastocyst development from implantation to survival into adulthood. In summary, overexpressing Kdm4b in donor cells only improved their reprogramming into early preimplantation stages, highlighting the need for alternative experimental approaches to reliably improve somatic cloning efficiency in cattle.