Abstract
Liver is the main organ of lipid metabolism in chicken, especially for laying hens. To explore the molecular mechanism of lipid metabolism in chicken, five novel genes discovered in chicken liver tissue were systematically studied. Bioinformatic analysis was used to analyze the gene characteristics. The expression patterns and regulatory molecular mechanism of the five genes were examined. Our results showed that all five novel genes contain a common NADP-binding site that belongs to the NADB-Rossmann superfamily, and the genes were designated NADB-LER1-5. Phylogenetic tree of the NADB-LERs gene family in different species suggested these five genes originated from the same ancestor. Tissue distributions showed that NADB-LER1-4 genes were highly expressed in lipid metabolism organs, including liver, kidney and duodenum, and that the NADB-LER5 gene was highly expressed in liver and kidney. The spatiotemporal expression indicated that the expression levels of NADB-LER1-5 genes in liver tissue were significantly greater in sexually mature hens than that of immature pullets (P-value ≤ 0.05). The expression levels of NADB-LER1-5 were significantly induced by 17β-estradiol in primary cultured chicken embryo hepatocytes (P-value ≤ 0.05), and 17β-estradiol regulated the expression of NADB-LER1-5 mediated by ERα. Individual assays verified that under induction of 17β-estradiol, the five novel genes were significantly upregulated, with subsequent alteration in serum TG, TC, and VLDLs in 10-week-old pullets. This study proved NADB-LERs family mainly expressed in liver, kidney, and duodenum tissues. 17β-estradiol induces the expression of NADB-LER1-5 genes predominantly mediated via ERα. They likely involved in lipid metabolism in the liver of chicken.
Highlights
In chicken, liver is the most important and central site for lipid synthesis, responsible for more than 90% of total fatty acid de novo synthesis (O’Hea and Leveille, 1969)
According to the Quantitative Real-Time PCR (qPCR) analysis, the five genes are significantly up-regulated in the liver tissue of 30 week hens relative to 20 week hens, which is in according with the RNA-seq data (Figure 1)
The results showed that compared with their levels in the control group, both ApoVLDL II and ApoB genes were significantly upregulated by different concentrations of estradiol, and they presented dose-dependent expression (P-value ≤ 0.05) in chicken hepatocytes (Figure 6)
Summary
Liver is the most important and central site for lipid synthesis, responsible for more than 90% of total fatty acid de novo synthesis (O’Hea and Leveille, 1969). During the egg-laying stage, under the influence of estrogen, many lipids including triacylglycerols, cholesteryl esters, and free fatty acids, are largely synthesized by the liver tissue. They are assembled into the egg-yolk precursors very low density lipoprotein (VLDL) and vitellogenin particles (Deeley et al, 1977), and transferred through blood circulation and deposited in the fast-growing oocyte (Brady et al, 1976; Wiskocil et al, 1980; Walzem et al, 1999; Nikolay et al, 2013). Lipid metabolism physiology is highly relevant to chicken embryonic growth development and the female reproductive system
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
