title: Microarray profiling for differential gene expression in PMSG-hCG stimulated preovulatory ovarian follicles of Chinese Taihu and Large White sows.
abstract: BACKGROUND
  The Chinese Taihu is one of the most prolific pig breeds in the world, which farrows at least five more piglets per litter than Western pig breeds partly due to a greater ovulation rate. Variation of ovulation rate maybe associated with the differences in the transcriptome of Chinese Taihu and Large White ovaries. In order to understand the molecular basis of the greater ovulation rate of Chinese Taihu sows, expression profiling experiments were conducted to identify differentially expressed genes in ovarian follicles at the preovulatory stage of a PMSG-hCG stimulated estrous cycle from 3 Chinese Taihu and 3 Large White cycling sows by using the Affymetrix Porcine Genechip™.
  
  
  RESULTS
  One hundred and thirty-three differentially expressed genes were identified between Chinese Taihu and Large White sows by using Affymetrix porcine GeneChip (p ≤ 0.05, Fold change ≥ 2 or ≤ 0.5). Gene Ontology (GO) analysis revealed that these genes belonged to the class of genes that participated in regulation of cellular process, regulation of biological process, biological regulation, developmental process, cell communication and signal transduction and so on. Significant differential expression of 6 genes including WNT10B and DKK2 in the WNT signaling pathway was detected. Real-time RT-PCR confirmed the expression pattern in seven of eight selected genes. A search of chromosomal location revealed that 92 differentially expressed transcripts located to the intervals of quantitative trait loci (QTLs) for reproduction traits. Furthermore, SNPs of two differentially expressed genes- BAX and BMPR1B were showed to be associated with litter size traits in Large White pigs and Chinese DIV line pigs (p ≤ 0.1 or p ≤ 0.05).
  
  
  CONCLUSIONS
  Our study detected many genes that showed differential expression between ovary follicles of two divergent breeds of pigs. Genes involved with regulation of cellular process, regulation of biological process, in addition to several genes not previously associated with ovarian physiology or with unknown function, were differentially expressed between two breeds. The suggestive or significant associations of BAX and BMPR1B gene with litter size indicated these genetic markers had the potentials to be used in pig industry after further validation of their genetic effects. Taken together, this study reveals many potential avenues of investigation for seeking new insights into ovarian physiology and the genetic control of reproduction.
authors.affiliation: Key Laboratory of Pig Genetics and Breeding of Ministry of Agriculture & Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, PR China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Sun
authors.forename: Shuqi
authors.initials: S
authors.lastname: Mei
authors.forename: Hu
authors.initials: H
authors.lastname: Tao
authors.forename: Guodong
authors.initials: G
authors.lastname: Wang
authors.forename: Lina
authors.initials: L
authors.lastname: Su
authors.forename: Siwen
authors.initials: S
authors.lastname: Jiang
authors.forename: Changyan
authors.initials: C
authors.lastname: Deng
authors.forename: Yuanzhu
authors.initials: Y
authors.lastname: Xiong
authors.forename: Fenge
authors.initials: F
authors.lastname: Li
mesh_terms: D000818:Animals; D001947:Breeding; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D019295:Computational Biology; D004338:Drug Combinations; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005787:Gene Frequency; D006064:Gonadotropins, Equine / Q000494:pharmacology; D008098:Litter Size / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D012098:Reproduction / Q000235:genetics; D013552:Swine / Q000235:genetics*
chemical_list: D006063:Chorionic Gonadotropin; D004338:Drug Combinations; D006064:Gonadotropins, Equine; C036835:PMSG-HCG