Saldana-Caboverde Amy, Perera Erasmo M, Watkins-Chow Dawn E, Hansen Nancy F, Vemulapalli Meghana, Mullikin James C, Pavan William J, Kos Lidia
Department of Biological Sciences, Florida International University, Miami, FL, USA.
Genetic Disease Research Branch, National Human Genome Institute, National Institutes of Health, Bethesda, MD, USA.
Dev Biol. 2015 Nov 15;407(2):300-12. doi: 10.1016/j.ydbio.2015.04.012. Epub 2015 Apr 23.
Melanocytes, the pigment-producing cells, arise from multipotent neural crest (NC) cells during embryogenesis. Many genes required for melanocyte development were identified using mouse pigmentation mutants. The variable spotting mouse pigmentation mutant arose spontaneously at the Jackson Laboratory. We identified a G-to-A nucleotide transition in exon 3 of the Ets1 gene in variable spotting, which results in a missense G102E mutation. Homozygous variable spotting mice exhibit sporadic white spotting. Similarly, mice carrying a targeted deletion of Ets1 exhibit hypopigmentation; nevertheless, the function of Ets1 in melanocyte development is unknown. The transcription factor Ets1 is widely expressed in developing organs and tissues, including the NC. In the chick, Ets1 is required for the expression of Sox10, a transcription factor critical for the development of various NC derivatives, including melanocytes. We show that Ets1 is required early for murine NC cell and melanocyte precursor survival in vivo. Given the importance of Ets1 for Sox10 expression in the chick, we investigated a potential genetic interaction between these genes by comparing the hypopigmentation phenotypes of single and double heterozygous mice. The incidence of hypopigmentation in double heterozygotes was significantly greater than in single heterozygotes. The area of hypopigmentation in double heterozygotes was significantly larger than would be expected from the addition of the areas of hypopigmentation of single heterozygotes, suggesting that Ets1 and Sox10 interact synergistically in melanocyte development. Since Sox10 is also essential for enteric ganglia development, we examined the distal colons of Ets1 null mutants and found a significant decrease in enteric innervation, which was exacerbated by Sox10 heterozygosity. At the molecular level, Ets1 was found to activate an enhancer critical for Sox10 expression in NC-derived structures. Furthermore, enhancer activation was significantly inhibited by the variable spotting mutation. Together, these results suggest that Ets1 and Sox10 interact to promote proper melanocyte and enteric ganglia development from the NC.
黑素细胞是产生色素的细胞，在胚胎发育过程中由多能神经嵴（NC）细胞产生。利用小鼠色素沉着突变体鉴定出了许多黑素细胞发育所需的基因。可变斑点小鼠色素沉着突变体在杰克逊实验室自发产生。我们在可变斑点小鼠中鉴定出Ets1基因外显子3中的一个G到A的核苷酸转换，这导致了一个错义G102E突变。纯合可变斑点小鼠表现出散发性白斑。同样，携带Ets1靶向缺失的小鼠表现出色素减退；然而，Ets1在黑素细胞发育中的功能尚不清楚。转录因子Ets1在包括神经嵴在内的发育中的器官和组织中广泛表达。在鸡中，Ets1是Sox10表达所必需的，Sox10是一种对包括黑素细胞在内的各种神经嵴衍生物的发育至关重要的转录因子。我们表明，Ets1在体内对小鼠神经嵴细胞和黑素细胞前体的存活是早期必需的。鉴于Ets1对鸡中Sox10表达的重要性，我们通过比较单杂合子和双杂合子小鼠的色素减退表型来研究这两个基因之间潜在的遗传相互作用。双杂合子中色素减退的发生率显著高于单杂合子。双杂合子中色素减退的面积显著大于单杂合子色素减退面积之和所预期的面积，这表明Ets1和Sox10在黑素细胞发育中协同作用。由于Sox10对肠神经节发育也至关重要，我们检查了Ets1基因敲除突变体的远端结肠，发现肠神经支配显著减少，而Sox10杂合性会加剧这种情况。在分子水平上，发现Ets1激活了一个对神经嵴衍生结构中Sox10表达至关重要的增强子。此外，可变斑点突变显著抑制了增强子的激活。总之，这些结果表明Ets1和Sox10相互作用以促进神经嵴正常的黑素细胞和肠神经节发育。
