Establishing the GRN for the Germ Line Mesoderm of Axolotl Embryos

精子细胞和卵细胞是由胚胎发育早期形成的原始生殖细胞（PGCs）产生的。了解PGCs在胚胎发育过程中是如何形成的是很重要的，因为它将导致生育治疗，也因为发育不良的精子和卵子会导致胚胎发育问题。由于不可能对人类胚胎进行研究，人们对PGCs是如何在人类体内形成的知之甚少。此外，与人类有许多共同特征的小鼠胚胎也在子宫内发育，而且非常小，因此很难获得。我们开发了一个实验系统，使用一种叫做蝾螈的蝾螈的胚胎。与哺乳动物的胚胎不同，蝾螈的胚胎非常大，它们在水中发育，因此一次很容易获得数百个胚胎。而且，由于它们不在子宫内发育，胚胎可以通过自然受精获得，而不会对成人造成伤害。然而，在这项研究中，美西螈的独特之处在于，美西螈胚胎使用与人类相同的基因产生PGCs，这使得与制造PGCs有关的基因很容易识别。我们开发了一种方法，在非常特殊的条件下一次生产数千个PGCs。因为细胞是如此丰富，我们将能够做DNA测序来识别基因，并做实验来了解基因是如何相互作用的。我们的实验结果将使我们能够开发出从胚胎干细胞中产生精子细胞和卵子的新方法，这是现代医学的主要目标。

Sperm cells and egg cells are produced from cells that form early in embryonic development called primordial germ cells, or PGCs. Understanding how PGCs are established during development of the embryos is important because it will lead to fertility treatments, and also because poorly formed sperm and eggs can give rise to embryos with developmental problems. Little is known about how PGCs are formed in humans because it is impossible to work with human embryos. In addition, mouse embryos, which share many characteristics with humans, also develop in a uterus, and are very small, and therefore are difficult to access. We developed an experimental system using embryos from a salamander called an axolotl. Unlike embryos from mammals, axolotl embryos are very large and they develop in water, and therefore hundreds of embryos are easy to acquire at a time. Also, because they do not develop in a uterus, the embryos can be acquired from natural fertilization, without harm to the adults. What makes axolotls unique for this study, however, is the fact that axolotl embryos produce PGCs using the same genes that humans do, and this makes the genes involved in making PGCs easy to identify. We developed a way to produce thousands of PGCs at a time using very specific conditions. Because the cells are so abundant we will be able to do DNA sequencing to identify the genes and do experiments to understand how the genes interact with each other. The results from our experiments will allow us to develop new ways to produce sperm cells and eggs from embryonic stem cells, which is a major goal of modern medicine.