Molecular cloning of adipose triglyceride lipase (ATGL) gene from blunt snout bream and its expression after LPS-induced TNF-α factor.

Abstract

The aims of the present study were to clone the full-length cDNA of adipose triglyceridelipase (ATGL) and to analyze its expression after lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-α). The cDNA obtained covered 1801bp with an open reading frame of 1500bp encoding 499 amino acids. Sequence alignment and phylogenetic analysis show the best identity with Cyprinus carpio (86%). The ATGL protein shared a highly conserved 169-amino acid patatin domain, containing a glycine-rich motif, an active serine hydrolase motif, and an aspartic active site. The highest ATGL expression was observed in the liver followed by muscle, whereas relatively low values were detected in the brain and adipose. TNF-α is regarded as an important factor in regulating fat metabolism. Here, LPS was used to induce TNF-α in vivo to verify whether TNF-α can affect ATGL expression. TNF-α expression in liver and muscle is increased and remains unchanged in adipose tissue and brain. The variation of ATGL activity is consistent with that of TNF-α gene expression. Next, we explored the mechanism by which LPS-induced TNF-α mediates the mRNA expression of ATGL in the liver and muscle. For liver, the mRNA levels of c-Jun N-terminal kinase (JNK), nuclear factor kappa B (NF-κB), Sirtuin 1 (SIRT1), and AMP-activated protein kinase (AMPK) were increased by LPS-induced TNF-α. Differencing from the situation in the liver, there was a near-significant decrease trend in the expression of SIRT1 in muscle. Those results indicated that the ATGL gene of blunt snout bream shared a high similarity with the other vertebrates. The expression level of ATGL in tissues with high-fat content was intended to be high. LPS can induce ATGL expression perhaps related to TNF-α.