Dpl is largely dispensable for embryonic development
Dpl is largely dispensable for embryonic development
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DOI：
10.1128/mcb.24.16.7197-7205.2004
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发表时间：
2004-08-01
影响因子：
5.3
通讯作者：
Yamasaki, L
中科院分区：
文献类型：
--
作者：
Kohn, MJ;Leung, SW;Yamasaki, L
E2F/DP复合体激活或抑制E2F靶基因的转录，这取决于PRB家族成员的关联，从而调节细胞周期进程。E2F家族由七个成员组成，而DP家族只有两个成员(DP1和DP2)，DP1是表达较高的成员。与单个E2F家族成员的失活相反，我们最近证明了DP1的丢失会导致胚胎12.5天(E12.5)的胚胎死亡，这是由于胚外血统无法正确地发育和复制DNA所致。为了绕过这一胎盘要求并寻找DP1在胚胎中的作用，我们产生了携带rosa26-LacZ标记的DP1缺陷的胚胎干细胞(ES)，并将它们注射到野生型囊胚中，以构建DP1缺陷的嵌合体。令人惊讶的是，我们发现了妊娠中期到晚期的胚胎(E12.5到E17.5)，X-Gal(5-bromo-4-chloro-3-indolyl-p-D-galactopyranoside)染色和Western blotting表明，在这些胚胎中，Dp1缺陷的ES细胞对大多数嵌合组织有很强的贡献。重要的是，在缺乏DP1的ES细胞或嵌合E15.5组织中，DP2蛋白的丰度不会增加，一系列细胞周期基因的表达几乎没有变化。因此，DP1在很大程度上是胚胎发育所必需的，尽管DP1在胚胎外是绝对需要的，这很容易让人想起Rb和细胞周期蛋白E1/E2在体内的有限作用。
E2F/DP complexes activate or repress the transcription of E2F target genes, depending on the association of a pRB family member, thereby regulating cell cycle progression. Whereas the E2F family consists of seven members, the DP family contains only two (Dp1 and Dp2), Dp1 being the more highly expressed member. In contrast to the inactivation of individual E2F family members, we have recently demonstrated that loss of Dp1 results in embryonic lethality by embryonic day 12.5 (E12.5) due to the failure of extraembryonic lineages to develop and replicate DNA properly. To bypass this placental requirement and search for roles of Dp1 in the embryo proper, we generated Dp1-deficient embryonic stem (ES) cells that carry the ROSA26-LacZ marker and injected them into wild-type blastocysts to construct Dp1-deficient chimeras. Surprisingly, we recovered mid- to late gestational embryos (E12.5 to E17.5), in which the Dp1-deficient ES cells contributed strongly to most chimeric tissues as judged by X-Gal (5-bromo-4-chloro-3-indolyl-p-D-galactopyranoside) staining and Western blotting. Importantly, the abundance of DP2 protein does not increase and the expression of an array of cell cycle genes is virtually unchanged in Dp1-deficient ES cells or chimeric E15.5 tissues with the absence of Dp1. Thus, Dp1 is largely dispensable for embryonic development, despite the absolute extraembryonic requirement for Dp1, which is highly reminiscent of the restricted roles for Rb and cyclins E1/E2 in vivo.