Wu Tsung-Chieh J, Wang Lai, Wan Yu-Jui Y
Department of Obstetrics and Gynecology, University of California at Los Angeles (UCLA) School of Medicine, Los Angeles, CA 90024, USA.
Department of Pathology, Harbor UCLA Medical Center, Torrance, CA 90509, USA.
Dev Growth Differ. 1992 Dec;34(6):685-691. doi: 10.1111/j.1440-169X.1992.tb00037.x.
Retinoic Acid, mediated through its receptors (RAR), exhibits striking effects on cell proliferation, differentiation, and pattern formation. At least three types of RARs (α, β, and γ) have been cloned. The ontogeny and semi-quantitated amount of three RAR mRNA were studied in mouse embryos and placentas using reverse transcriptase-polymerase chain reaction technique. The amplified cDNA products were confirmed by correct sizes, Southern blot hybridization and restriction enzyme digestion. The results show that RAR-α mRNA is constitutively expressed in the oocytes and embryos of all stages, suggesting that RAR-α is a housekeeping gene. RAR-β mRNA is present in the oocytes, becomes undetectable at the 2-cell stage when the maternal RNA is degraded, and re-expresses at morula and blastocyst stages when the embryonic genome is activated. RAR-γ mRNA is not expressed until balstocyst stage. In the postimplantation embryos, no significant change in all three RAR mRNA levels was detected from day 10 through the late gestational stage (day 18). Placental tissue expressed all three RAR transcripts throughout gestation. The differential activation of the these three RAR genes in the preimplantation embryos suggests RARs as the important regulators during early embryogenesis.
视黄酸通过其受体（RAR）介导，对细胞增殖、分化和模式形成具有显著影响。至少已克隆出三种类型的RAR（α、β和γ）。利用逆转录-聚合酶链反应技术，研究了小鼠胚胎和胎盘中三种RAR mRNA的个体发生和半定量含量。通过正确的大小、Southern印迹杂交和限制性内切酶消化对扩增的cDNA产物进行了确认。结果表明，RAR-α mRNA在所有阶段的卵母细胞和胚胎中均组成性表达，提示RAR-α是一个管家基因。RAR-β mRNA存在于卵母细胞中，在2细胞期母体RNA降解时无法检测到，而在桑椹胚和囊胚期胚胎基因组激活时重新表达。RAR-γ mRNA直到囊胚期才表达。在植入后胚胎中，从第10天到妊娠晚期（第18天），未检测到所有三种RAR mRNA水平有显著变化。胎盘组织在整个妊娠期均表达所有三种RAR转录本。植入前胚胎中这三种RAR基因的差异激活表明RAR是早期胚胎发育过程中的重要调节因子。
