Zhou Quan-Yong, Fang Ming-Di, Huang Ting-Hua, Li Chang-Chun, Yu Mei, Zhao Shu-Hong
Key Laboratory of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education & Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, PR China.
BMC Genomics. 2009 Jul 26;10:337. doi: 10.1186/1471-2164-10-337.
Placental efficiency is strongly associated with litter size, fetal weight and prenatal mortality. Together with its rapid growth during late gestation, the Large White pig breed shows a significant increase in placental size and weight, but this does not occur in the highly prolific Chinese pig breeds. To understand the molecular basis of placental development during late gestation in Chinese indigenous and Western breeds with different placental efficiency, female placental samples were collected from six pregnant Erhualian gilts at gestation day 75 (E75) and day 90 (E90) and from six pregnant Large White gilts at gestation day 75 (L75) and day 90 (L90). Two female placentas from one sow were used to extract RNA and then pooled in equal volumes. Twelve pooled samples were hybridized to the porcine Affymetrix GeneChip.
A total of 226 and 577 transcripts were detected that were differentially expressed between E75 and L75 and between E90 and L90 (p < 0.01, q < 0.2), respectively. Gene Ontology (GO) analysis revealed that these genes belong to the class of genes that participate in angiogenesis and development. Real-time RT-PCR confirmed the differential expression of eight selected genes. Significant differential expression of five genes in the VEGF pathway was also detected between the breeds. A search of chromosomal location revealed that 44 differentially expressed genes located to QTL regions related to reproduction. Differential expression of six candidate imprinted genes was also confirmed. Three of the six genes (PLAGL1, DIRAS3, and SLC38A4) showed monoallelic expression in the porcine placenta.
Our study detected many genes that showed differential expression between placentas of two divergent breed of pigs, and confirmed the imprinting of three genes. These findings help to elucidate the genetic control of placental efficiency and improve the understanding of placental development.
胎盘效率与产仔数、胎儿体重和产前死亡率密切相关。大白猪品种在妊娠后期生长迅速，胎盘大小和重量显著增加，但高产的中国猪品种却并非如此。为了解不同胎盘效率的中国本土猪种和西方猪种在妊娠后期胎盘发育的分子基础，在妊娠第75天（E75）和第90天（E90）从6头怀孕的二花脸母猪采集雌性胎盘样本，在妊娠第75天（L75）和第90天（L90）从6头怀孕的大白母猪采集雌性胎盘样本。从一头母猪的两个雌性胎盘提取RNA，然后等体积混合。将12个混合样本与猪Affymetrix基因芯片杂交。
分别在E75和L75之间以及E90和L90之间检测到226个和577个差异表达的转录本（p < 0.01，q < 0.2）。基因本体论（GO）分析表明，这些基因属于参与血管生成和发育的基因类别。实时RT-PCR证实了8个选定基因的差异表达。在两个品种之间还检测到VEGF途径中5个基因的显著差异表达。对染色体定位的搜索显示，44个差异表达基因位于与繁殖相关的QTL区域。还证实了6个候选印记基因的差异表达。6个基因中的3个（PLAGL1、DIRAS3和SLC38A4）在猪胎盘中表现为单等位基因表达。
我们的研究检测到许多在两个不同猪品种的胎盘之间差异表达的基因，并证实了3个基因的印记。这些发现有助于阐明胎盘效率的遗传控制，并增进对胎盘发育的理解。
