Overexpression of G0/G1 Switch Gene 2 in Adipose Tissue of Transgenic Quail Inhibits Lipolysis Associated with Egg Laying

Abstract

Abstract:In avians, yolk synthesis is regulated by incorporation of portomicrons from the diet, transport of lipoproteins from the liver, and release of lipids from adipose tissue; however, the extent to which lipolysis in adipose tissue contributes to yolk synthesis and egg production has yet to be elucidated. G0/G1 switch gene 2 (G0S2) is known to bind and inhibit adipose triglyceride lipase (ATGL), the rate-limiting enzyme in lipolysis. The objective of this study was to determine whether overexpression of the G0S2 gene in adipose tissue could successfully inhibit endogenous ATGL activity associated with egg laying. Two independent lines of transgenic quail overexpressing G0S2 had delayed onset of egg production and reduced number of eggs over a six-week period compared to non-transgenic quail. Although no differences in measured parameters were observed at the pre-laying stage (5 weeks of age), G0S2 transgenic quail had significantly larger interclavicular fat pad weights and adipocyte sizes and lower NEFA concentrations in the serum at early (1 week after laying first egg) and active laying (5 weeks after laying first egg) stages. Overexpression of G0S2 inhibited lipolysis during early and active laying, which drastically shifted the balance towards a net accumulation of triacylglycerols and increased adipose tissue mass. Thereby, egg production was negatively affected as less triacylglycerols were catabolized to produce lipids for the yolk.

Identification of the MUC2 Promoter as a Strong Promoter for Intestinal Gene Expression through Generation of Transgenic Quail Expressing GFP in Gut Epithelial Cells

“…The specific pattern of gene expression in certain types of cells, particular developmental stages, and nutritional conditions has been shown to be regulated by conserved regulatory elements, including a promoter region found in previous studies along with our reports [ 4 , 5 , 19 , 20 , 21 ]. In the current study, conserved promoter regions were identified in the chicken MUC2 gene that are specifically expressed in intestinal tissues of 7-week-old broiler chickens.…”

Effects of Fermented Idesia Polycarpa Residues supplementation on laying performance of Laying Quails

“…Apo very low density lipoprotein II (APOVLDL-II) is related to the secretion of VLDL, which plays a pivotal role in egg formation (19). The described changes in the fat pad and ATGL expression found in the study by Chen et al (40) were also observed in our study ( Fig. 1-III ).…”

“…As we know that both fatty acid and cholesterol metabolism are involved in the regulation of egg formation (40, 41), and lipid mobilization from the adipose tissue is one of the main sources supporting the onset of egg production. As a result of lipid mobilization, the increase in the fat pad is the most intuitive indication of a supply of raw material available for egg production (42).…”

Deficiency of Brummer Impaires Lipid Mobilization and JH-Mediated Vitellogenesis in the Brown Planthopper, Nilaparvata lugens

“…In mammal, adipose triglyceride lipases (ATGLs) play critical roles in TAG mobilization, and ATGL mutation results in the accumulation of TAG and FAs in plasma (Zechner et al, 2007 ). In Japanese quail , ATGL knockdown shifts the balance toward a net accumulation of TAG in fat tissues and reduces number of eggs (Chen et al, 2016 ). At least two kinds of lipases have been documented to play important roles in the maintenance of insect lipid homeostasis by regulating lipolysis in the fat body.…”