Do H3K4 methyltransferases MLL4 and MLL3 instruct the mammalian body plan?

H3K4 甲基转移酶 MLL4 和 MLL3 是否指导哺乳动物的身体规划？

• 批准号: 426821658
• 负责人: Dr. Andrea Kranz
• 金额: --
• 依托单位: Biotechnologisches Zentrum (Biotec)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/426821658?language=en
• 关键词: Do; H3K4; methyltransferases; MLL4; MLL3

The major epigenetic regulator, MLL4, is prominently mutated in many cancers and is one of six mammalian histone 3 lysine 4 (H3K4) methyltransferases. Heterozygous mutations of MLL4 provoke Kabuki syndrome, which involves mental retardation, facial and other morphological changes, and metabolic disorders. Despite its medical importance, the role of MLL4 in mouse development has only been partially examined. We have been systematically documenting the embryonic roles of all six H3K4 methyltransferases and report that Mll4 null embryos undergo defective gastrulation owing to a defect in establishing the anterior visceral endoderm (AVE) and consequently, the anterior-posterior (A-P) axis during early development. To probe later into development, we generated a new loxP conditional Mll4 allele. Using Sox2Cre, we identified a role for MLL4 in the epiblast and using R26CreERT2 with tamoxifen-induction at different times, found evidence for MLL4 contribution until the completion of A-P axis elongation at E13.5. We propose that MLL4 is continuously required for neuromesodermal progenitor (NMP) specification of trunk elongation, segmentation and the tail, potentially exerted through regulation of Hox cluster colinearity. Conditional mutagenesis also revealed that MLL3, which is not required until birth, can substitute for MLL4 during the elongation of the A-P axis. Using conditional mutagenesis in utero and in embryonic stem cell lines (ESCs) established from our conditional knockout mouse lines, we aim to dissect the contributions of MLL4 (and MLL3) to the establishment of the mammalian body plan. We will investigate whether embryonic development can be recapitulated in vitro through NMPs and gastruloids in the absence of MLL4 (+/-MLL3) with a focus on colinear induction of Hox cluster expression. These analyses include a structure/function dissection of MLL4 using a deletion series of Mll4 BAC transposons introduced into the conditional Mll4 ESCs. Using in situ hybridization, imaging techniques, and conditional mutagenesis methods developed in part by our lab, together with expression profiling, deep sequencing and in vitro embryogenesis, we aim to identify the relationship between MLL4 (and MLL3) in specification of the mammalian body plan.

主要的表观遗传调节因子MLL 4在许多癌症中显著突变，并且是六种哺乳动物组蛋白3赖氨酸4（H3 K4）甲基转移酶之一。MLL 4的杂合突变引起Kabuki综合征，其涉及精神发育迟滞、面部和其他形态学变化以及代谢紊乱。尽管MLL 4在医学上具有重要意义，但它在小鼠发育中的作用仅得到部分研究。我们已经系统地记录了所有六个H3 K4甲基转移酶的胚胎作用，并报告说，M114无效胚胎经历有缺陷的原肠胚形成由于在建立前内脏内胚层（AVE）的缺陷，因此，在早期发育过程中的前-后（A-P）轴。为了稍后探索发育，我们产生了新的loxP条件性M114等位基因。使用Sox 2Cre，我们确定了MLL 4在上胚层中的作用，并在不同时间使用R26 CreERT 2与他莫昔芬诱导，发现了MLL 4贡献的证据，直到E13.5完成A-P轴伸长。我们建议，MLL 4是持续需要的神经中胚层祖细胞（NMP）规格的躯干伸长，分割和尾巴，可能通过调节Hox集群共线性。条件诱变还显示，MLL 3，这是不需要的，直到出生，可以取代MLL 4在延长A-P轴。使用条件突变在子宫内和胚胎干细胞系（ESC）建立从我们的条件敲除小鼠系，我们的目标是剖析MLL 4（和MLL 3）的贡献，建立哺乳动物的身体计划。我们将研究在MLL 4（+/-MLL 3）不存在的情况下，胚胎发育是否可以通过NMP和gastruloids在体外重演，重点是Hox簇表达的共线诱导。这些分析包括MLL 4的结构/功能解剖，使用引入条件M114 ESC的M114 BAC转座子的缺失系列。使用原位杂交，成像技术和条件诱变方法，部分由我们的实验室开发，再加上表达谱，深度测序和体外胚胎发生，我们的目标是确定MLL 4（和MLL 3）之间的关系在哺乳动物身体计划的规范。