Temporally controlled targeted somatic mutagenesis in embryonic surface ectoderm and fetal epidermal keratinocytes unveils two distinct developmental functions of BRG1 in limb morphogenesis and skin barrier formation
Temporally controlled targeted somatic mutagenesis in embryonic surface ectoderm and fetal epidermal keratinocytes unveils two distinct developmental functions of BRG1 in limb morphogenesis and skin barrier formation
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DOI：
10.1242/dev.02019
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发表时间：
2005-10-01
期刊：
影响因子：
4.6
通讯作者：
Metzger, D
中科院分区：
文献类型：
--
作者：
Indra, AK;Dupé, V;Metzger, D
动物SWI 2/SNF 2蛋白复合物含有brahma（BRM）或brahma相关基因1（BRG 1）ATP酶，参与核小体重塑，并可能控制序列特异性转录因子对DNA的可及性。体外研究表明，BRM和BRG 1可以调节不同基因组的表达。然而，由于缺乏BRM的小鼠是可行的和可生育的，BRG 1可能有效地补偿BRM损失。相比之下，由于Brg 1-null成纤维细胞是可行的，但Brg 1-null胚胎在围着床期死亡，BRG 1可能发挥细胞特异性功能。为了进一步研究BRG 1的体内作用，我们选择性地消融形成小鼠表皮的角质形成细胞中的Brg 1。我们表明，BRG 1是选择性地需要在肢体图案的上皮间充质相互作用，并在角质形成细胞的终端分化，其中BRM可以部分替代BRG 1。相比之下，BRM和BRG 1都不是角质形成细胞增殖和早期分化所必需的，这可能需要其他ATP依赖的核小体重塑复合物。最后，我们证明，在细胞特异性表达他莫昔芬可激活的Cre-ERT 2重组酶的小鼠胚胎发育过程中，可以在不同时间产生细胞特异性靶向体细胞突变。
Animal SWI2/SNF2 protein complexes containing either the brahma (BRM) or brahma-related gene 1 (BRG1) ATPase are involved in nucleosome remodelling and may control the accessibility of sequence-specific transcription factors to DNA. In vitro studies have indicated that BRM and BRG1 could regulate the expression of distinct sets of genes. However, as mice lacking BRM are viable and fertile, BRG1 might efficiently compensate for BRM loss. By contrast, as Brg1-null fibroblasts are viable but Brg1-null embryos die during the peri-implantation stage, BRG1 might exert cell-specific functions. To further investigate the in vivo role of BRG1, we selectively ablated Brg1 in keratinocytes of the forming mouse epidermis. We show that BRG1 is selectively required for epithelial-mesenchymal interactions in limb patterning, and during keratinocyte terminal differentiation, in which BRM can partially substitute for BRG1. By contrast, neither BRM nor BRG1 are essential for the proliferation and early differentiation of keratinocytes, which may require other ATP-dependent nucleosome-remodelling complexes. Finally, we demonstrate that cell-specific targeted somatic mutations can be created at various times during the development of mouse embryos cell-specifically expressing the tamoxifen-activatable Cre-ERT2 recombinase.