title: Altered imprinted gene expression and methylation patterns in mid-gestation aborted cloned porcine fetuses and placentas.
abstract: OBJECTIVE
  To determine the expression patterns of imprinted genes and their methylation status in aborted cloned porcine fetuses and placentas.
  
  
  METHODS
  RNA and DNA were prepared from fetuses and placentas that were produced by SCNT and controls from artificial insemination. The expression of 18 imprinted genes was determined by quantitative real-time PCR (q-PCR). Bisulfite sequencing PCR (BSP) was conducted to determine the methylation status of PRE-1 short interspersed repetitive element (SINE), satellite DNA and H19 differentially methylated region 3 (DMR3).
  
  
  RESULTS
  The weight, imprinted gene expression and genome-wide DNA methylation patterns were compared between the mid-gestation aborted and normal control samples. The results showed hypermethylation of PRE-1 and satellite sequences, the aberrant expression of imprinted genes, and the hypomethylation of H19 DMR3 occurred in mid-gestation aborted fetuses and placentas.
  
  
  CONCLUSIONS
  Cloned pigs generated by somatic cell nuclear transfer (SCNT) showed a greater ratio of early abortion during mid-gestation than did normal controls because of the incomplete epigenetic reprogramming of the donor cells. Altered expression of imprinted genes and the hypermethylation profile of the repetitive regions (PRE-1 and satellite DNA) may be associated with defective development and early abortion of cloned pigs, emphasizing the importance of epigenetics during pregnancy and implications thereof for patient-specific embryonic stem cells for human therapeutic cloning and improvement of human assisted reproduction.
authors.affiliation: Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, 130062, China, recsy1126@163.com.
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Zhang
authors.forename: Dongxu
authors.initials: D
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Han
authors.forename: Feifei
authors.initials: F
authors.lastname: Duan
authors.forename: Qinyan
authors.initials: Q
authors.lastname: Lv
authors.forename: Zhanjun
authors.initials: Z
authors.lastname: Li
mesh_terms: D000034:Abortion, Veterinary / Q000235:genetics*; D000818:Animals; D019976:Cloning, Organism; D019175:DNA Methylation; D004276:DNA, Satellite / Q000737:chemistry; D044127:Epigenesis, Genetic; D005260:Female; D020869:Gene Expression Profiling; D018392:Genomic Imprinting; D053652:Nuclear Transfer Techniques; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D013552:Swine / Q000235:genetics*
chemical_list: D004276:DNA, Satellite