title: Imprinted mesodermal specific transcript (MEST) and H19 genes in renal development and diabetes.
abstract: BACKGROUND
  Imprinted genes, mesodermal specific cDNA or transcript (MEST) and H19, are implicated in peri-implantation embryogenesis, and their expression was assessed in embryonic kidneys undergoing glucose-induced dysmorphogenesis.
  
  
  METHODS
  MEST and H19 mRNA expression was assessed by Northern blot analysis in embryonic kidneys of mice harvested at day 15 to day 19 of gestation and of 1-week-old mice obtained from hyperglycemic mothers. A full-length mouse MEST cDNA was isolated, subcloned into an expression vector, a recombinant protein prepared and an antibody raised; the latter was used to assess protein expression by immunoprecipitation and immunofluorescence microscopy in day 13 metanephric explants subjected to high glucose ambience. Also, MEST mRNA expression was assessed in high d glucose-treated explants by competitive reverse transcription-polymerase chain reaction (RT-PCR) analyses and by in situ tissue autoradiography.
  
  
  RESULTS
  A high expression of MEST and H19 with respective transcript size of approximately 2.7 and approximately 2.4 kb was observed in fetal kidneys, and their expression decreased during the successive stages of gestation and was undetectable in the postnatal period. At day 13, the MEST mRNA was expressed in the mesenchyme, while H19 was expressed in the ureteric bud branches and epithelial elements of the metanephros. Their expression decreased with progression of gestation. By competitive RT-PCR and Northern blot and in situ autoradiographic analyses, both MEST and H19 expressions decreased in day 13 explants treated with high glucose and in the kidneys of fetuses obtained from diabetic mothers. The MEST protein expression was observed in the metanephric epithelial elements and ureteric bud branches instead of in the mesenchyme, and its expression decreased in glucose-treated dysmorphogenetic explants, as assessed by immunofluorescence and immunoprecipitation methods.
  
  
  CONCLUSIONS
  MEST and H19 imprinted genes are strategically located in the mammalian embryonic metanephros. They are developmentally regulated and their concomitant decreased expression in high glucose ambience or diabetic state did not follow the prevailing dogma of reciprocal inactivation/activation of imprinted genes, and such a decrease may be responsible for the perturbed epithelial:mesenchymal interactions leading to dysmorphogenesis of the mammalian metanephros.
authors.affiliation: Departments of Pathology, Northwestern University Medical School, Chicago, Illinois 60611, USA. y-kanwar@northwestern.edu
authors.forename: Yashpal S
authors.initials: YS
authors.lastname: Kanwar
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Pan
authors.forename: Sun
authors.initials: S
authors.lastname: Lin
authors.forename: Anil
authors.initials: A
authors.lastname: Kumar
authors.forename: Jun
authors.initials: J
authors.lastname: Wada
authors.forename: Christian S
authors.initials: CS
authors.lastname: Haas
authors.forename: Gene
authors.initials: G
authors.lastname: Liau
authors.forename: Jon W
authors.initials: JW
authors.lastname: Lomasney
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D003928:Diabetic Nephropathies / Q000503:physiopathology*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018392:Genomic Imprinting; D005947:Glucose / Q000494:pharmacology; D006943:Hyperglycemia / Q000503:physiopathology; D007668:Kidney / Q000196:embryology / Q000502:physiology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009924:Organ Culture Techniques; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000503:physiopathology; D011506:Proteins / Q000235:genetics* / Q000276:immunology / Q000494:pharmacology; D062085:RNA, Long Noncoding; D012333:RNA, Messenger / Q000032:analysis; D022661:RNA, Untranslated / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology
chemical_list: D000906:Antibodies; C094335:H19 long non-coding RNA; D011506:Proteins; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D022661:RNA, Untranslated; D011993:Recombinant Fusion Proteins; C103637:mesoderm specific transcript protein; D005947:Glucose