Griffith Oliver W, Ujvari Beata, Belov Katherine, Thompson Michael B
School of Biological Sciences, University of Sydney, Sydney, NSW, Australia.
J Exp Zool B Mol Dev Evol. 2013 Nov;320(7):465-70. doi: 10.1002/jez.b.22526. Epub 2013 Aug 12.
Viviparity (live birth) relies on a functional placenta, which is formed by cooperating maternal and embryonic tissues. In some viviparous lineages, mothers use this placenta to transport nutrients to feed developing embryos through pregnancy (placentotrophy). The Australian lizard, Pseudemoia entrecasteauxii, provides approximately 60% of the lipid for embryonic growth and metabolism to embryos across the placenta. Lipoprotein lipase (LPL) is an important enzyme in lipid transport in vertebrates. We examined patterns of LPL gene expression to identify its role in the uterus of pregnant P. entrecasteauxii. We used reverse transcription quantitative real time PCR to measure the expression of the LPL gene in the uterine tissue throughout reproduction and compared uterine LPL expression in chorioallantoic and yolk-sac placentae. Expression of the LPL gene is significantly higher in the uterus of late pregnant compared to non-pregnant and early pregnant P. entrecasteauxii, indicating a greater capacity for lipid transport towards the end of pregnancy. The period of high LPL gene expression correlates with the time that developing embryos are undergoing the greatest growth and have the highest metabolic rate. LPL gene expression is significantly higher in the uterine tissue of the yolk-sac placenta than the chorioallantoic placenta, providing the first molecular evidence that the yolk-sac placenta is the major site of lipid transport in pregnant P. entrecasteauxii.
胎生（活体分娩）依赖于功能性胎盘，胎盘由母体和胚胎组织协同形成。在一些胎生谱系中，母体利用这个胎盘在孕期输送营养物质来滋养发育中的胚胎（胎盘营养）。澳大利亚蜥蜴——恩氏伪蜥，通过胎盘为胚胎提供约60%的脂质用于胚胎生长和代谢。脂蛋白脂肪酶（LPL）是脊椎动物脂质运输中的一种重要酶。我们研究了LPL基因的表达模式，以确定其在怀孕的恩氏伪蜥子宫中的作用。我们使用逆转录定量实时PCR来测量整个生殖过程中子宫组织中LPL基因的表达，并比较绒毛尿囊胎盘和卵黄囊胎盘的子宫LPL表达。与未怀孕和怀孕早期的恩氏伪蜥相比，怀孕后期的恩氏伪蜥子宫中LPL基因的表达显著更高，这表明在怀孕末期脂质运输能力更强。LPL基因高表达期与发育中的胚胎生长最快、代谢率最高的时期相关。卵黄囊胎盘的子宫组织中LPL基因表达显著高于绒毛尿囊胎盘，这提供了首个分子证据，表明卵黄囊胎盘是怀孕的恩氏伪蜥脂质运输的主要部位。
