Stachowiak M, Szydlowski M, Flisikowski K, Flisikowska T, Bartz M, Schnieke A, Switonski M
Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637 Poznan, Poland.
Chair of Livestock Biotechnology, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany.
J Anim Sci. 2014 Jun;92(6):2363-71. doi: 10.2527/jas.2013-7509. Epub 2014 Mar 26.
The PPARA (peroxisome proliferator-activated receptor-α) gene encodes a nuclear receptor that plays an important role in fatty acid catabolism by transcriptional regulation of genes involved in fatty acid oxidation and can be considered as a candidate gene for fatness traits in the pig. The aim of the study was to search for a functional polymorphism in 3' untranslated region (UTR), their association with production traits, and postnatal PPARA transcript level in 2 skeletal muscles (longissimus and semimembranosus) of 5 commercial pig breeds (Polish Landrace [PL], Polish Large White [PLW], Duroc, Pietrain, and Pulawska). Altogether, 9 novel polymorphisms (8 SNP and 1 indel) were found in the 3' UTR. The in silico analysis revealed 6 putative microRNA target sequences in the analyzed region. The c.*636A>G substitution was widely distributed across breeds and located near the putative target sequence for miR-224. The relative PPARA transcript level was higher (P < 0.05) in LM of AA than in those of GG homozygous animals for SNP c.*636A>G. The luciferase assay revealed that miR-224 probably acts as a negative regulator of the PPARA expression in pig adipocytes (P = 2.9 × 10(-7)), but we did not observe the effect of the A or G alleles on the interaction between miR-224 and its putative target sequence. We hypothesize that the 2 predominant haplotypes, differing at 4 sites (including c.*636A>G), present different architecture of its 3' UTR and it could affect the level of the transcript. The c.*636A>G SNP, analyzed in PL and PLW, was significantly associated with backfat thickness at 3 points (P < 0.05) and intramuscular fat content (P < 0.01) in PL. Suggestive associations were found between 4 SNP (c.*321A>C, c.*324G>C, c.*626T>C, and c.*636A>G) and fatty acid contents in LM and subcutaneous and visceral fat tissue of PL, PLW, Duroc and Pietrain pigs. The PPARA mRNA level was higher in semimembranosus muscle than in LM (P = 8.38 × 10(-12)) in a general comparison and the same trend was found in most breeds (except for PL) and at all tested days of age (60, 90, 120, 150, 180, and 210 d). The effect of breed was highly significant in a general comparison (P = 0.48 × 10(-8)), but there was no common expression pattern in both muscles among different age groups. We conclude that the c.*636A>G SNP in the PPARA gene can be considered in PL breed as a useful genetic marker for adipose tissue accumulation.
过氧化物酶体增殖物激活受体α（PPARA）基因编码一种核受体，该受体通过对参与脂肪酸氧化的基因进行转录调控，在脂肪酸分解代谢中发挥重要作用，可被视为猪脂肪性状的候选基因。本研究旨在寻找3'非翻译区（UTR）的功能性多态性、其与生产性状的关联以及5个商业猪品种（波兰长白猪[PL]、波兰大白猪[PLW]、杜洛克猪、皮特兰猪和普瓦夫猪）2种骨骼肌（背最长肌和半膜肌）出生后PPARA转录水平。共在3'UTR中发现9个新的多态性（8个单核苷酸多态性和1个插入缺失）。电子分析揭示了分析区域中有6个假定的微小RNA靶序列。c.*636A>G替换在各品种中广泛分布，且位于miR-224的假定靶序列附近。对于单核苷酸多态性c.*636A>G，AA基因型动物背最长肌中的PPARA相对转录水平高于GG纯合动物（P<0.05）。荧光素酶检测表明，miR-224可能是猪脂肪细胞中PPARA表达的负调控因子（P = 2.9×10⁻⁷），但我们未观察到A或G等位基因对miR-224与其假定靶序列之间相互作用的影响。我们推测，2种主要单倍型在4个位点（包括c.*636A>G）存在差异，其3'UTR具有不同结构，这可能影响转录水平。在PL和PLW中分析的c.*636A>G单核苷酸多态性与3个点的背膘厚（P<0.05）和PL中的肌内脂肪含量（P<0.01）显著相关。在PL、PLW、杜洛克猪和皮特兰猪的背最长肌、皮下脂肪组织和内脏脂肪组织中，发现4个单核苷酸多态性（c.*321A>C、c.*324G>C、c.*626T>C和c.*636A>G）与脂肪酸含量之间存在提示性关联。在总体比较中，半膜肌中的PPARA mRNA水平高于背最长肌（P = 8.38×10⁻¹²），且在大多数品种（PL除外）以及所有测试日龄（60、90、120、150、180和210日龄）均发现相同趋势。在总体比较中，品种效应高度显著（P = 0.48×10⁻⁸），但不同年龄组的两种肌肉中没有共同的表达模式。我们得出结论，PPARA基因中的c.*636A>G单核苷酸多态性在PL品种中可被视为脂肪组织积累的有用遗传标记。
