甲状旁腺激素相关蛋白在着床前小鼠胚胎中的定位与囊胚孵化事件有关。
Localization of parathyroid hormone-related protein in the preimplantation mouse embryo is associated with events of blastocyst hatching.
机构信息
Department of Animal Sciences, University of Illinois, 310 Animal Science Laboratory, 1207 W. Gregory Drive, Urbana, IL, 61801, USA.
出版信息
J Assist Reprod Genet. 2013 Aug;30(8):1009-15. doi: 10.1007/s10815-013-0094-y.
PURPOSE
To determine the pattern of expression of parathyroid hormone-related protein (PTHrP) and its receptor, parathyroid hormone receptor 1 (PTHR1), in mouse embryos in different stages of preimplantation development.
METHODS
Embryos were cultured from the pronuclear zygote stage and harvested as 2-cell, 4-cell and 8-cell embryos, morulae and blastocysts. RT-PCR was carried out on mRNAs of these and of trophoblast outgrowths for detection of PTHrP and PTHR1. Whole mounted embryos intact or stripped of zonae pellucidae were immunofluorescently stained for PTHrP and PTH receptor and observed with confocal microscopy.
RESULTS
PTHrP mRNA was present in the pronuclear zygote, not present in 2-cell, 4-cell and uncompacted 8-cell embryos, present in the 8-cell compacting embryo, and not detected in 16-cell morulae or blastocysts. The mRNA was present in trophoblasts growing on fibronectin beds. mRNA for PTHR1 was detected in the pronuclear zygote, then undetected until the compacted 8-cell stage and thereafter. PTH receptor protein was observed in 2-cell embryos, morulae and in the inner cell mass and trophectoderm of blastocysts. PTHrP was observed dispersed in the cytoplasm of 2-cell, 4-cell and uncompacted 8-cell embryos, and in distinct foci near the nuclei of morulae. In blastocysts, PTHrP appeared on the apical surface of only trophoblast cells which had extruded from the zona pellucida. Fully hatched blastocysts expressed the protein on the apical side of all trophoblasts. When morulae were prematurely stripped of their zonae, PTHrP was observed on the embryos' outer surface.
CONCLUSIONS
PTHrP protein is expressed throughout early embryo development, and its receptor PTHR1 is expressed from the morula stage. Embryo hatching is associated with translocation of PTHrP to the apical plasma membrane of trophoblasts. PTHrP may thus have autocrine effects on the developing blastocyst.
目的
确定甲状旁腺激素相关蛋白 (PTHrP) 和其受体甲状旁腺激素受体 1 (PTHR1) 在不同阶段的小鼠胚胎前植入发育中的表达模式。
方法
从原核合子阶段培养胚胎，并收获 2 细胞、4 细胞和 8 细胞胚胎、桑葚胚和胚泡。通过 RT-PCR 检测这些胚胎和滋养外胚层生长的 PTHrP 和 PTHR1 mRNA。对完整或去透明带的整体胚胎进行 PTHrP 和 PTH 受体免疫荧光染色，并通过共聚焦显微镜观察。
结果
PTHrP mRNA 存在于原核合子中，不存在于 2 细胞、4 细胞和未致密的 8 细胞胚胎中，存在于致密的 8 细胞胚胎中，在 16 细胞桑葚胚或胚泡中未检测到。mRNA 存在于在纤维连接蛋白床上生长的滋养层中。PTHR1 mRNA 在原核合子中被检测到，然后在致密的 8 细胞阶段未被检测到，此后未被检测到。PTH 受体蛋白在 2 细胞胚胎、桑葚胚和胚泡的内细胞团和滋养层中被观察到。在 2 细胞、4 细胞和未致密的 8 细胞胚胎中，PTHrP 被观察到分散在细胞质中，在桑葚胚的核附近有明显的焦点。在胚泡中，PTHrP 仅出现在已从透明带中挤出的滋养层细胞的顶端表面。完全孵化的胚泡在所有滋养层的顶端表面表达该蛋白。当桑葚胚过早地去除其透明带时，PTHrP 被观察到在胚胎的外表面。
结论
PTHrP 蛋白在整个早期胚胎发育过程中表达，其受体 PTHR1 从桑葚胚阶段开始表达。胚胎孵化与 PTHrP 向滋养层顶端质膜的转移有关。因此，PTHrP 可能对发育中的胚泡具有自分泌作用。
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