The uptake of macro- and micronutrients via a variety of transport systems. in the intestinal epithelium is essential for life. Transport of amino. acids in the form of di- and tripeptides is mediated by the intestinal. peptide transporter PEP-2 and triacylglyceroles are absorbed as fatty. acids, glycerol and monoacylglyceroles. Although the survival of C. elegans. is independent on dietary poly-unsaturated fatty acids (PUFAs), their in. vivo production seems to be linked to amino acid homeostasis.. In the present study we show that an abolished uptake of di- and. tripeptides by deletion of the
pep-2 gene leads to a reduced fat content. and to a conspicuous shift in fatty acid patterns in
pep-2(
lg601) C.. elegans. These animals contain 25% less total fat than wildtype animals. (based on Nile Red-staining and on GC measurements), which might be. partially based on transcriptional upregulation of genes involved in. lipolysis of triacylglycerides in the gut (incl. F46B6.8, homologous to. gastric triglyceride lipase/cholesterol esterase). Detailed analysis of the. fatty acid pattern of
pep-2 showed an accumulation of medium chain (16:1. and 18:1) mono-unsaturated fatty acids, while poly-unsaturated fatty acids. including arachidonic acid (20:4n6) were significantly reduced.. Transcriptome analysis assessed a consistently reduced gene expression for. desaturases (
fat-5,
fat-6,
fat-7) and elongases (
elo-1,
elo-2, elo- 5). acting in this part of fatty acid synthesis. Additionally, mRNA expression. levels of genes responsible for the peroxisomal beta-oxidation of long-chain. fatty acids was in total increased, suggesting a higher metabolic turnover. of long-chain fatty acids including PUFAs. All these metabolic changes lead. to a highly effective fat metabolism in
pep-2, which is essential for. survival and reproduction during amino acid deficiency.