Frankenberg S, Tisdall D, Selwood L
Department of Zoology, La Trobe University, Victoria, Australia.
Mol Reprod Dev. 2001 Mar;58(3):255-61. doi: 10.1002/1098-2795(200103)58:3<255::AID-MRD2>3.0.CO;2-3.
Several morphological features of early development differ between marsupials and eutherians. These include early overt conceptus polarity, the mode of segregation of pluriblast and trophoblast lineages, and the superficial position of the pluriblast within the unilaminar blastocyst epithelium. Knowledge of the molecular mechanisms of early development is lacking in marsupials. We have cloned from the brushtail possum, Trichosurus vulpecula, the partial cDNA of a marsupial homologue of mammalian POU5F1, which encodes octamer-binding transcription factor-4 (Oct-4). The 579 bp cloned coding sequence of possum POU5F1 (tvPOU5F1) shares 74, 78, and 79% identity with murine Pou5f1, human POU5F1, and bovine bPOU5F1, respectively, at the protein level. The mRNA for tvPOU5F1 was detected by in situ hybridization in oogonia and in oocytes of growing follicles, but not in early meiotic oocytes. In a gastrulation-stage conceptus, high tvPOU5F1 expression was found in the embryonic ectoderm, with low or undetectable expression in other cell types. These results are comparable with those of murine and bovine expression studies, and suggest that the putative role of POU5F1 in totipotent and pluripotent cells is conserved among mammals.
有袋类动物和有胎盘类动物在早期发育的几个形态学特征上存在差异。这些差异包括早期明显的孕体极性、多能胚层和滋养层谱系的分离方式，以及多能胚层在单层囊胚上皮内的浅表位置。目前对于有袋类动物早期发育的分子机制尚缺乏了解。我们从帚尾袋貂（Trichosurus vulpecula）中克隆了哺乳动物POU5F1有袋类同源物的部分cDNA，该基因编码八聚体结合转录因子4（Oct-4）。袋貂POU5F1（tvPOU5F1）克隆的579 bp编码序列在蛋白质水平上与小鼠Pou5f1、人类POU5F1和牛bPOU5F1的同一性分别为74%、78%和79%。通过原位杂交在卵原细胞和生长卵泡的卵母细胞中检测到了tvPOU5F1的mRNA，但在早期减数分裂卵母细胞中未检测到。在原肠胚形成阶段的孕体中，发现tvPOU5F1在胚胎外胚层中高表达，而在其他细胞类型中表达低或无法检测到。这些结果与小鼠和牛的表达研究结果相当，表明POU5F1在全能和多能细胞中的假定作用在哺乳动物中是保守的。
