| Novel high-throughput deep sequencing technology has dramatically changed the study of the functional complexity of transcriptomes. Here we reported the first use of this technology for analyzing the wide range of transcriptional changes in porcine adipose tissue from different breeds and different growth phases in a model of obesity. Digital gene expression (DGE) data sets were instrumental to verify the predicted gene models.The translationally controlled tumor protein (TCTP) expressed abundantly in a wide range of organisms from both the animal and plant kingdom, which initially described as a growth-related protein. However, the research showed that TCTP has a lot of biological functions. The expression of TCTP in fat tissues and adipocytes of different genotype pigs and in different growth periods were explored by high-throughout sequencing (Solexa) and real-time quantity PCR ( RT-qPCR), and its effect on differentiation of adipocytes was explored by siRNA.There are major results based on investigation above, as follows:1. A total of 3,562,453,3,524,793,3,762,623 hight quality tags were obtained from lean, obese-a and obese-b libraries. Tags amount of obese-b library was more 200,000 tags than the other libraries. A total of 89,782,98,467,72,881 distinct tags were obtained from lean, obese-a and obese-b libraries. Amount of distinct tags in the obese-a library were much more than the other libraries.2. A total of 2,817,553,2,869,303和2,889,733 hight quality tags from lean, obese-a and obese-b libraries were mapped the porcine reference genes databases. Mapping efficiency of tags from three libraries were 79.09%,81.4%,76.8% respectively.3. We found the expression level of 1596 genes was different significantly between lean and obese-a library. Among them, 84 genes only expressed in obese-a library and 95 genes only expressed in lean library. Moreover, the expression of 4403 genes was found to be remarkably different between obese-a and obese-b library, and 642 genes of them only expressed in obese-a and 618 genes only expressed in obese-b library. There are 574 genes expressed in three libraries. 4. When mapping to genes, it was found that the sense transcripts account for 67.42%, 68.65%, and 66.61% of all clean tags in the lean, obese-a, and obese-b libraries respectively. Otherwise, it was found that the antisense transcripts account for 11.66%,12.74% and 10.2%. By comparison, the ratio of sense to antisense mapping of the total number of tags was approximately 6:1 for all libraries.5. We anticipated more than 20,000 different novel tags to be localized to the porcine genome. Among them, 799 different clean tags with a copy number of more than 1000 were detected.6. Different genes between lean and obese-a libraries were enriched significenty at 13 terms from the component Ontology, one terms from the function Ontology and one terms from the process Ontology. Otherwise, different genes between obese-a and obese-b libraries were enriched significenty at 42 terms from the component Ontology, 12 terms from the function Ontology and 26 terms from the process Ontology.7. Between the different growth phase (obese-a and obese-b), statistical test of the significantly different UniGene transcripts revealed significant enrichment of genes groups in pathway involved in metabolic pathways, lysosome, DNA replication, amino sugar and nucleotide sugar metabolism, glycolysis / gluconeogenesis, arginine/proline metabolism, peroxisome, pentose phosphate pathway, pyruvate metabolism, purine metabolism and nucleotide sugar metabolism. Amino sugar and nucleotide sugar metabolism, lysosome, DNA replication, VEGF signaling pathway, nicotinate and nicotinamide metabolism were observed significantly enriched pathways between lean and obese-a library.8.We observed that 6,19,13,3,5,6,9 different genes between lean and obese-a to play respectively a role in the Notch signaling pathway, MAPK signaling pathway, PPAR signaling pathway, Hedgehog signaling pathway, Adipocytokine signaling pathway, Insulin signaling pathway, WNT signaling pathway.9. We observed that 15,45,22,3,13,28,25 different genes between obese-a and obese-b to play respectively a role in the Notch signaling pathway, MAPK signaling pathway, PPAR signaling pathway, Hedgehog signaling pathway, Adipocytokine signaling pathway, Insulin signaling pathway, WNT signaling pathway.10. The results showed that expressions level of TCTP were higher in the fat tissues of lean-type pig than that of obese-type; Expressions level of TCTP in the porcine fat tissue and adipocyte were influenced by ages, and showed a higher expression in heart, liver, kidney, muscle and fat, but lower in spleen and lung.11. Silencing TCTP by siRNA promoted the adipocytes to differentiate and significantly increased expressions level of PPARγ, C/EBPαand SREBP-1c. TCTP may inhibit adipogenesis by this study which will provide new theoretical reference for fat deposition control. |
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