着床期的胚胎死亡率显著影响猪的窝产仔数。孕激素旁分泌信号已被证明对胚胎着床有重要作用。IHH、NR2F2、BMP2、FKBP4、HAND2都被证明参与了孕激素旁分泌信号。本研究的目的是评估怀孕母猪子宫内膜IHH、NR2F2、BMP2、FKBP4、HAND2的表达量及进一步探讨这些基因对窝产仔数的影响。实时PCR、蛋白质印迹、免疫染色方法用于分析猪子宫内膜目标基因的表达量。RFLP-PCR用于检测目标基因单核甘酸多态性。
 

　　结果
 

　　研究结果表明胚胎着床期母猪子宫内膜上IHH、NR2F2、BMP2的mRNAT 和蛋白质表达量均上升。所有基因主要分布于子宫腔上皮和腺上皮。有趣的是，基质中 NR2F2、HAND2的染色也很明显。单核甘酸多态性检测发现NR2F2基因的启动区存在一个-204C>A突变。且发现大白、长白、杜洛克母猪存在三个基因型。研究记录了625头母猪的NR2F2的基因型及总共1847窝仔猪数，用于分析NR2F2的基因型与母猪窝产总数、窝产活仔数的关系。结果表明CC基因型母猪窝产仔数更大。
 

　　总结
 

　　这项研究表明胚胎着床期内母猪子宫内相关基因/蛋白质的表达参与了孕激素旁分泌信号。并从这些信号中鉴定了一个候选基因。这些研究对进一步探讨这些基因在猪胚胎着床期的作用有一定的参考价值。
 

　　附原文：
 

　　Expression of genes involved in progesterone receptor paracrine signaling and their effect on litter size in pigs
 

　　Abstract
 

　　Background
 

　　Embryonic mortality during the period of implantation strongly affects litter size in pigs. Progesterone receptor (PGR) paracrine signaling has been recognized to play a significant role in embryonic implantation.IHH, NR2F2, BMP2, FKBP4 and HAND2 were proved to involve in PGR paracrine signaling. The objective of this study was to evaluate the expression of IHH, NR2F2, BMP2, FKBP4 and HAND2 in endometrium of pregnant sows and to further investigate these genes' effect on litter size in pigs. Real-time PCR, western blot and immunostaining were used to study target genes/proteins expression in endometrium in pigs. RFLP-PCR was used to detect single nucleotide polymorphisms (SNPs) of target genes.
 

　　Results
 

　　The results showed that the mRNA and protein expression levels of IHH, NR2F2 and BMP2 were up-regulated during implantation period (P < 0.05 or P < 0.01)。 All target proteins were mainly observed in luminal epithelium and glandular epithelium. Interestingly, the staining of NR2F2 and HAND2 was also strong in stroma. SNPs detection revealed that there was a -204C > A mutation in promoter region of NR2F2gene. Three genotypes were found in Large White, Landrace and Duroc sows. A total of 1847 litter records from 625 sows genotyped at NR2F2 gene were used to analyze the total number born (TNB) and number born alive (NBA)。 The study of the effect on litter size suggested that sows with genotype CC tend to have higher litter size.
 

　　Conclusions
 

　　These results showed the expression patterns of genes/proteins involved in PGR paracrine signaling over implantation time. And the candidate gene for litter size was identified from genes involved in this signaling. This study could be a resource for further studies to identify the roles of these genes for embryonic implantation in pigs.