title: Epigenetic and SP1-mediated regulation is involved in the repression of galactokinase 1 gene in the liver of neonatal piglets born to betaine-supplemented sows.
abstract: OBJECTIVE
  In this study, we sought to investigate the effects of maternal betaine supplementation on the expression and regulation of GALK1 gene in the liver of neonatal piglets.
  
  
  METHODS
  Sixteen sows of two groups were fed control or betaine-supplemented diets (3 g/kg), respectively, throughout the pregnancy. Newborn piglets were individually weighed immediately after birth, and one male piglet close to mean body weight from the same litter was selected and killed before suckling. Serum samples of newborn piglets were analyzed for biochemical indexes, hormone and amino acid levels. Liver samples were analyzed for GALK1 expression by real-time PCR and western blotting, while GALK1 regulational mechanism was analyzed by methylated DNA immunoprecipitation, chromatin immunoprecipitation and microRNAs expression.
  
  
  RESULTS
  Betaine-exposed neonatal piglets had lower serum concentration of galactose, which was associated with significantly down-regulated hepatic GALK1 expression. The repression of GALK1 mRNA expression was associated with DNA hypermethylation and more enriched repression histone mark H3K27me3 on its promoter. Binding sites of SP1, GR and STAT3 were predicted on GALK1 promoter, and decreased SP1 protein content and lower SP1 binding to GALK1 promoter were detected in the liver of betaine-exposed piglets. Furthermore, the expression of miRNA-149 targeting GALK1 was up-regulated in the liver of betaine-exposed piglets, along with elevated miRNAs-processing enzymes Dicer and Ago2.
  
  
  CONCLUSIONS
  Our results suggest that maternal dietary betaine supplementation during gestation suppresses GALK1 expression in the liver of neonatal piglets, which involves complex gene regulation mechanisms including DNA methylation, histone modification, miRNAs expression and SP1-mediated transcriptional modulation.
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
authors.forename: Demin
authors.initials: D
authors.lastname: Cai
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
authors.forename: Mengjie
authors.initials: M
authors.lastname: Yuan
authors.affiliation: Department of Medical Cell Biology, University of Uppsala, 75123, Uppsala, Sweden.
authors.forename: Haoyu
authors.initials: H
authors.lastname: Liu
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
authors.forename: Zhengqiang
authors.initials: Z
authors.lastname: Han
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.|College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China.
authors.forename: Shifeng
authors.initials: S
authors.lastname: Pan
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China. zhao.ruqian@gmail.com.|Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing, 210095, People's Republic of China. zhao.ruqian@gmail.com.
authors.forename: Ruqian
authors.initials: R
authors.lastname: Zhao
mesh_terms: D000596:Amino Acids / Q000097:blood; D000818:Animals; D000831:Animals, Newborn; D001622:Betaine / Q000008:administration & dosage* / Q000097:blood; D015415:Biomarkers / Q000097:blood; D047369:Chromatin Immunoprecipitation; D019175:DNA Methylation / Q000187:drug effects; D004032:Diet; D019587:Dietary Supplements; D063185:Epigenetic Repression; D005260:Female; D005686:Galactokinase / Q000235:genetics* / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D005786:Gene Expression Regulation; D007328:Insulin / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D011401:Promoter Regions, Genetic; D015203:Reproducibility of Results; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D013552:Swine
chemical_list: D000596:Amino Acids; D015415:Biomarkers; D007328:Insulin; D035683:MicroRNAs; D016329:Sp1 Transcription Factor; D001622:Betaine; D005686:Galactokinase; D005690:Galactose
keywords: Betaine; Galactokinase 1; Galactose; Methylation; Piglets; miRNA-149