Yanagisawa H, Yanagisawa M, Kapur R P, Richardson J A, Williams S C, Clouthier D E, de Wit D, Emoto N, Hammer R E
Howard Hughes Medical Institute, Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75235-9050, USA.
Development. 1998 Mar;125(5):825-36. doi: 10.1242/dev.125.5.825.
Recent gene targeting studies have revealed unexpected roles for endothelins in the development of neural crest-derived tissues. Endothelin converting enzyme-1 (ECE-1) catalyzes the proteolytic activation of big endothelin-1 to endothelin-1(ET-1) in vitro. However, the importance of ECE-1 cleavage in the multiple endothelin pathways in vivo is unknown. Here we generated a targeted null mutation in the mouse ECE-1 gene. ECE-1-/- term embryos exhibited craniofacial and cardiac abnormalities virtually identical to the defects seen in ET-1 and endothelin A receptor (ETA)-deficient embryos. Epidermal melanocytes as well as enteric neurons of the distal gut were also absent in ECE-1-/- embryos, reproducing the developmental phenotype seen in ET-3-/- and endothelin B receptor (ETB)-/- mice. Surprisingly, large amounts of mature ET-1 peptide are found in ECE-1-/- embryos, indicating that non-ECE-1 protease(s) can activate ET-1 at certain sites. However, these enzymes cannot produce sufficient mature endothelin at the locations crucial for normal embryonic development. These findings reveal that ECE-1 is a bona fide activating protease for both big ET-1 and big ET-3 in vivo, and that the cell-cell communication pathways represented by the ET-1/ECE-1/ETA axis and the ET-3/ECE-1/ETB axis are each involved in the development of distinct subsets of neural crest cell lineages. Mutations in ECE-1 may cause developmental defects in humans, such as Hirschsprung disease, velocardiofacial syndrome and related neurocristopathies.
最近的基因靶向研究揭示了内皮素在神经嵴衍生组织发育中的意外作用。内皮素转换酶-1（ECE-1）在体外催化大内皮素-1蛋白水解激活为内皮素-1（ET-1）。然而，ECE-1切割在体内多种内皮素途径中的重要性尚不清楚。在此，我们在小鼠ECE-1基因中产生了靶向无效突变。ECE-1基因敲除的足月胚胎表现出颅面和心脏异常，与ET-1和内皮素A受体（ETA）缺陷胚胎中所见的缺陷几乎相同。ECE-1基因敲除胚胎中也没有表皮黑素细胞以及远端肠道的肠神经元，重现了ET-3基因敲除和内皮素B受体（ETB）基因敲除小鼠中所见的发育表型。令人惊讶的是，在ECE-1基因敲除胚胎中发现了大量成熟的ET-1肽，表明非ECE-1蛋白酶可以在某些位点激活ET-1。然而，这些酶在对正常胚胎发育至关重要的位置不能产生足够的成熟内皮素。这些发现揭示了ECE-1在体内是大ET-1和大ET-3的真正激活蛋白酶，并且由ET-1/ECE-1/ETA轴和ET-3/ECE-1/ETB轴代表的细胞间通讯途径各自参与神经嵴细胞谱系不同亚群的发育。ECE-1的突变可能导致人类发育缺陷，如先天性巨结肠、心脏颜面综合征和相关的神经嵴病。
