Li Cheng, Lan Yahui, Schwartz-Orbach Lianna, Korol Evgenia, Tahiliani Mamta, Evans Todd, Goll Mary G
Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Program in Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY 10065, USA.
Department of Surgery, Weill Cornell Medical College, New York, NY 10065, USA.
Cell Rep. 2015 Aug 18;12(7):1133-43. doi: 10.1016/j.celrep.2015.07.025. Epub 2015 Aug 6.
The Tet family of methylcytosine dioxygenases (Tet1, Tet2, and Tet3) convert 5-methylcytosine to 5-hydroxymethylcytosine. To date, functional overlap among Tet family members has not been examined systematically in the context of embryonic development. To clarify the potential for overlap among Tet enzymes during development, we mutated the zebrafish orthologs of Tet1, Tet2, and Tet3 and examined single-, double-, and triple-mutant genotypes. Here, we identify Tet2 and Tet3 as the major 5-methylcytosine dioxygenases in the zebrafish embryo and uncover a combined requirement for Tet2 and Tet3 in hematopoietic stem cell (HSC) emergence. We demonstrate that Notch signaling in the hemogenic endothelium is regulated by Tet2/3 prior to HSC emergence and show that restoring expression of the downstream gata2b/scl/runx1 transcriptional network can rescue HSCs in tet2/3 double mutant larvae. Our results reveal essential, overlapping functions for tet genes during embryonic development and uncover a requirement for 5hmC in regulating HSC production.
四氢叶酸家族的甲基胞嘧啶双加氧酶（Tet1、Tet2和Tet3）可将5-甲基胞嘧啶转化为5-羟甲基胞嘧啶。迄今为止，尚未在胚胎发育的背景下系统研究Tet家族成员之间的功能重叠情况。为了阐明发育过程中Tet酶之间潜在的重叠功能，我们对斑马鱼中Tet1、Tet2和Tet3的直系同源基因进行了突变，并检测了单突变、双突变和三突变基因型。在此，我们确定Tet2和Tet3是斑马鱼胚胎中主要的5-甲基胞嘧啶双加氧酶，并发现造血干细胞（HSC）出现过程中对Tet2和Tet3存在联合需求。我们证明，在HSC出现之前，造血内皮中的Notch信号受Tet2/3调控，并表明恢复下游gata2b/scl/runx1转录网络的表达可挽救tet2/3双突变幼虫中的HSC。我们的结果揭示了tet基因在胚胎发育过程中至关重要的重叠功能，并发现了5hmC在调节HSC产生中的需求。
