Duan Kui, Sun Yingning, Zhang Xiaofei, Zhang Tianmu, Zhang Wenjian, Zhang Jiyang, Wang Guihua, Wang Shouzhi, Leng Li, Li Hui, Wang Ning
Key Laboratory of Chicken Genetics and Breeding, Ministry of Agriculture Key Laboratory of Animal Genetics, Breeding and Reproduction, Education Department of Heilongjiang Province. College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang 150030, China.
Key Laboratory of Chicken Genetics and Breeding, Ministry of Agriculture Key Laboratory of Animal Genetics, Breeding and Reproduction, Education Department of Heilongjiang Province. College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang 150030, China College of Life Science and Agriculture Forestry, Qiqihar University, Qiqihar, Heilongjiang 161006, China.
Poult Sci. 2015 Oct;94(10):2516-27. doi: 10.3382/ps/pev229. Epub 2015 Aug 17.
Peroxisome proliferator-activated receptor gamma regulates adipogenesis. The genomic structure of the chicken peroxisome proliferator-activated receptor gamma (cPPARγ) gene has not been fully characterized, and only one cPPARγ gene mRNA sequence has been reported in genetic databases. Using 5' rapid amplification of cDNA ends, we identified five different cPPARγ mRNAs that are transcribed from three transcription initiation sites. The open reading frame analysis showed that these five cPPARγ transcript variants (cPPARγ1 to 5) could encode two cPPARγ protein isoforms (cPPARγ1 and cPPARγ2), which differ only in their N-terminal region. Quantitative real-time RT-PCR analysis showed that, of these five cPPARγ transcript variants, cPPARγ1 was ubiquitously highly expressed in various chicken tissues, including adipose tissue, liver, kidney, spleen and duodenal; cPPARγ2 was exclusively highly expressed in adipose tissue; cPPARγ3 was highly expressed in adipose tissue, kidney, spleen and liver; cPPARγ4 and cPPARγ5 were ubiquitously weakly expressed in all the tested tissues, and comparatively, cPPARγ5 was highly expressed in adipose tissue, heart, liver and kidney. The comparison of the expression of the five cPPARγ transcript variants showed that adipose tissue cPPARγ1 expression was significantly higher in the fat line than in the lean line from 2 to 7 wk of age (P < 0.05 or P < 0.01). Adipose tissue cPPARγ3 expression was significantly higher in the fat line than in the lean line at 3, 5 and 6 wk of age (P < 0.01, P < 0.05), but lower at 4 wk of age (P < 0.05). Adipose tissue cPPARγ5 expression was significantly higher in the fat line than in the lean line at 3, 4, and 6 wk of age (P < 0.01) and at 2 and 7 wk of age (P < 0.05). This is the first report of transcript variants and protein isoforms of cPPARγ gene. Our findings provided a foundation for future investigations of the function and regulation of cPPARγ gene in adipose tissue development.
过氧化物酶体增殖物激活受体γ调节脂肪生成。鸡过氧化物酶体增殖物激活受体γ（cPPARγ）基因的基因组结构尚未完全明确，遗传数据库中仅报道了一个cPPARγ基因的mRNA序列。利用5' cDNA末端快速扩增技术，我们鉴定出了5种不同的cPPARγ mRNA，它们由3个转录起始位点转录而来。开放阅读框分析表明，这5种cPPARγ转录变体（cPPARγ1至5）可编码两种cPPARγ蛋白异构体（cPPARγ1和cPPARγ2），它们仅在N端区域有所不同。实时定量RT-PCR分析显示，在这5种cPPARγ转录变体中，cPPARγ1在包括脂肪组织、肝脏、肾脏、脾脏和十二指肠在内的各种鸡组织中普遍高表达；cPPARγ2仅在脂肪组织中高表达；cPPARγ3在脂肪组织、肾脏、脾脏和肝脏中高表达；cPPARγ4和cPPARγ5在所有测试组织中普遍低表达，相对而言，cPPARγ5在脂肪组织、心脏、肝脏和肾脏中高表达。对5种cPPARγ转录变体表达情况的比较表明，在2至7周龄时，脂肪组织中cPPARγ1的表达在脂肪系中显著高于瘦肉系（P < 0.05或P < 0.01）。在3、5和6周龄时，脂肪组织中cPPARγ3的表达在脂肪系中显著高于瘦肉系（P < 0.01，P < 0.05），但在4周龄时较低（P < 0.05）。在3、4和6周龄以及2和7周龄时，脂肪组织中cPPARγ5的表达在脂肪系中显著高于瘦肉系（P < 0.01）和（P < 0.05）。这是关于cPPARγ基因转录变体和蛋白异构体的首次报道。我们的研究结果为今后研究cPPARγ基因在脂肪组织发育中的功能和调控奠定了基础。
