Jiao Ze-Xu, Xu Min, Woodruff Teresa K
J Assist Reprod Genet. 2014 Jun;31(6):731-7. doi: 10.1007/s10815-014-0210-7.
To confirm that aneuploidy candidate genes are detectable in the first polar body (PB(1)) of MII oocytes and to investigate the age-dependent molecular changes in PB(1).
Aged (12-to 15-mo-old) and young (2-mo-old) mice were administered pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotrophin (hCG). MII oocytes were obtained and the first PB was removed. mRNA from each PB and its sibling oocyte was reverse transcribed. Real-time PCR was performed to quantify the expression of six genes (BUB1, CDC20, Filia, MCAK, SGOL1, SMC1A) in single PB.
We first demonstrated that detection and quantification of transcripts associated with aneuploidy in single mouse oocyte and sibling PB(1) is possible and the relative abundance of mRNA transcripts in a single PB faithfully reflects the relative abundance of that transcript in its sibling oocyte. We further found that transcript levels were significantly lower in aged PBs compared with young PBs (P<0.05).
Our results suggest that the detection and analysis of polar body mRNA may provide insight in age-related aneuploidy in oocyte. This analysis is a novel concept to investigate the genesis of chromosome abnormality and could potentially assist in the characterization of mechanisms underlying key molecular origin of female meiotic aneuploidy, which would be of great scientific and clinical value.
确认在第二次减数分裂中期（MII）卵母细胞的第一极体（PB1）中可检测到非整倍体候选基因，并研究PB1中与年龄相关的分子变化。
对老龄（12至15月龄）和年轻（2月龄）小鼠注射孕马血清促性腺激素（PMSG）和人绒毛膜促性腺激素（hCG）。获取MII卵母细胞并去除第一极体。将每个极体及其对应的卵母细胞的mRNA进行逆转录。采用实时定量PCR技术对单个极体中六个基因（BUB1、CDC20、Filia、MCAK、SGOL1、SMC1A）的表达进行定量分析。
我们首次证明，在单个小鼠卵母细胞及其对应的PB1中检测和定量与非整倍体相关的转录本是可行的，单个PB中mRNA转录本的相对丰度忠实地反映了其对应的卵母细胞中该转录本的相对丰度。我们还发现，老龄极体中的转录本水平显著低于年轻极体（P<0.05）。
我们的结果表明，极体mRNA的检测和分析可能有助于深入了解与年龄相关的卵母细胞非整倍体情况。这种分析是研究染色体异常发生机制的一个新概念，可能有助于阐明女性减数分裂非整倍体关键分子起源的潜在机制，具有重要的科学和临床价值。
