title: Hepatic patatin-like phospholipase domain-containing protein 3 sequence, single nucleotide polymorphism presence, protein confirmation, and responsiveness to energy balance in dairy cows.
abstract: Patatin-like phospholipase domain-containing protein 3 (PNPLA3), commonly known as adiponutrin, is part of a novel subfamily of triglyceride lipase enzymes with potential effects on triglyceride metabolism in adipose and hepatic tissues. The predicted bovine PNPLA3 sequence has been identified, but expression of the gene had not been examined. The objectives of this study were to confirm the predicted bovine PNPLA3 gene sequence, determine expression of the bovine PNPLA3 gene in response to whole-animal energy balance, identify single nucleotide polymorphisms present in dairy cows, and verify the presence of the protein in the liver. Using liver biopsy samples collected from cows at +28d relative to calving (DRTC), RNA was isolated and used to generate a cDNA template for amplification of the entire predicted coding sequence of PNPLA3 via PCR. To determine if energy balance alters the expression of PNPLA3, RNA was isolated and mRNA expression quantified in liver samples from mid-lactation cows after a 5-d ad libitum period (n=5) and after a subsequent 5-d 50% feed restriction period (n=5), and in samples collected from cows at -14, +1, +14, and +28 DRTC (n=16). The presence of PNPLA3 protein was detected by Western blot in liver protein samples collected at +28 DRTC. Expression of hepatic PNPLA3 was decreased after a period of feed restriction (8.14 vs. 1.08±2.17 arbitrary units, ad libitum vs. fasted). Expression of PNPLA3 mRNA was decreased at +1 and +14 DRTC compared with -14 DRTC (23.35, 7.28, 10.17, and 14.5±4.9 arbitrary units, -14, +1, +14, and +28 DRTC, respectively). The presence of PNPLA3 protein was detected as a 55-kDa band in hepatic protein isolations from liver tissue collected at +28 DRTC. These data confirm the presence and sequence of the bovine hepatic PNPLA3 gene and single nucleotide polymorphisms. Furthermore, these data indicate responsiveness of bovine hepatic PNPLA3 to energy balance.
authors.affiliation: Department of Animal Science, University of Connecticut, Storrs 06269.
authors.forename: Christine C
authors.initials: CC
authors.lastname: McCann
authors.affiliation: Department of Animal Science, University of Connecticut, Storrs 06269.
authors.forename: Molly E
authors.initials: ME
authors.lastname: Viner
authors.affiliation: Department of Animal Sciences, Purdue University, West Lafayette, IN 47907.
authors.forename: Shawn S
authors.initials: SS
authors.lastname: Donkin
authors.affiliation: Department of Dairy Science, University of Wisconsin, Madison 53706. Electronic address: hwhite4@wisc.edu.
authors.forename: H M
authors.initials: HM
authors.lastname: White
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D007774:Lactation; D050356:Lipid Metabolism / Q000502:physiology*; D008099:Liver / Q000378:metabolism; D010740:Phospholipases / Q000737:chemistry / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D012333:RNA, Messenger; D010740:Phospholipases
keywords: adiponutrin; lipase; phospholipase domain-containing protein 3 (PNPLA3); transition cow