title: Endometrial gene expression profiling in pregnant Meishan and Yorkshire pigs on day 12 of gestation.
abstract: BACKGROUND
  Litter size in pigs is a major factor affecting the profitability in the pig industry. The peri-implantation window in pigs is characterized by the coordinated interactions between the maternal uterine endometrium and the rapidly elongating conceptuses and represents a period of time during which a large percentage of the developing conceptuses are lost. However, the gene expression and regulatory networks in the endometrium contributing to the establishment of the maternal: placental interface remain poorly understood.
  
  
  RESULTS
  We characterized the endometrial gene expression profile during the peri-implantation stage of development by comparing two breeds that demonstrate very different reproductive efficiencies. We employed the porcine Affymetrix GeneChip® to assay the transcriptomic profiles of genes expressed in the uterine endometrium obtained from Meishan and Yorkshire gilts (n = 4 for each breed) on day 12 of gestation (M12 and Y12, respectively). Total of 17,076 probesets were identified as "present" in at least two arrays. A mixed model-based statistical analysis predicted a total of 2,656 (q < 0.1) transcripts as differentially expressed between Meishan and Yorkshire pigs. Eighteen differentially expressed transcripts of interest were validated by quantitative real-time PCR. Gene ontology (GO) annotation revealed that the known functions of the differentially expressed genes were involved in a series of important biological processes relevant to early pregnancy establishment in the pig.
  
  
  CONCLUSIONS
  The results identified endometrial gene expression profiles of two breeds differing in litter size and identified candidate genes that are related to known physiological pathways related to reproductive prolificacy. These findings provide a deeper understanding of molecular pathways differing between two breeds at the critical peri-implantation stage of pregnancy, which can be utilized to better understand the events contributing to pregnancy establishment in the pig.
authors.forename: Ting
authors.initials: T
authors.lastname: Gu
authors.forename: Meng-jin
authors.initials: MJ
authors.lastname: Zhu
authors.forename: Martine
authors.initials: M
authors.lastname: Schroyen
authors.forename: Long
authors.initials: L
authors.lastname: Qu
authors.forename: Dan
authors.initials: D
authors.lastname: Nettleton
authors.forename: Dan
authors.initials: D
authors.lastname: Kuhar
authors.forename: Joan K
authors.initials: JK
authors.lastname: Lunney
authors.forename: Jason W
authors.initials: JW
authors.lastname: Ross
authors.affiliation: Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan 430070, P, R, China. shzhao@mail.hzau.edu.cn.
authors.forename: Shu-hong
authors.initials: SH
authors.lastname: Zhao
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Tuggle
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D019295:Computational Biology; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D053263:Gene Regulatory Networks; D008098:Litter Size; D058977:Molecular Sequence Annotation; D011247:Pregnancy; D015203:Reproducibility of Results; D013552:Swine; D059467:Transcriptome