Department of Zoology, University of Melbourne, Melbourne, Victoria, Australia.
Mol Hum Reprod. 2010 Aug;16(8):539-47. doi: 10.1093/molehr/gaq042. Epub 2010 May 25.
Male and female preimplantation mammalian embryos differ not only in their chromosomal complement, but in their proteome and subsequent metabolome. This phenomenon is due to a finite period during preimplantation development when both X chromosomes are active, between embryonic genome activation and X chromosome inactivation, around the blastocyst stage. Consequently, prior to implantation male and female embryos exhibit differences in their cellular phenotype. Manifestations of such differences include altered total activity of specific X-linked enzymes and the metabolic pathways they regulate. Subsequently, one would expect to be able to determine differences in the rate of consumption and utilization of specific nutrients between male and female embryos. Data to date on animal models support this, with sex-specific differences in glucose and amino acid utilization being reported for the mouse and cow blastocysts. Such differences in metabolic phenotype may logically be involved in the reported differences in growth rates between preimplantation embryos of different sex. As the fields of proteomics and metabolomics are being increasingly applied to human assisted conception it is prudent to consider how such technologies may be applied to identify sex differences in the human embryo. Such data would have implications far beyond current invasive technologies used to identify the sex of an embryo conceived in vitro for the diagnosis of X-linked diseases.
雄性和雌性哺乳动物胚胎在植入前不仅在染色体组成上有所不同，而且在其蛋白质组和随后的代谢组上也存在差异。这种现象是由于在胚胎基因组激活和 X 染色体失活之间的植入前发育的有限时期内，两个 X 染色体都具有活性，大约在囊胚阶段。因此，在植入前，雄性和雌性胚胎在其细胞表型上表现出差异。这些差异的表现包括特定 X 连锁酶的总活性改变及其调节的代谢途径。随后，人们期望能够确定雄性和雌性胚胎对特定营养素的消耗和利用速度之间的差异。迄今为止，动物模型的数据支持这一点，已报道了小鼠和牛囊胚中葡萄糖和氨基酸利用的性别特异性差异。这种代谢表型的差异可能在报告的不同性别植入前胚胎的生长速度差异中具有逻辑意义。随着蛋白质组学和代谢组学领域越来越多地应用于人类辅助受孕，明智的做法是考虑如何应用这些技术来识别人类胚胎中的性别差异。这些数据的意义远远超出了目前用于体外受精胚胎的性别鉴定的侵入性技术，用于 X 连锁疾病的诊断。
