Molecular characterization and gene silencing using double-strand RNA of adiponectin receptor in white-leg shrimp, Litopenaeus vannamei

Abstract

Adiponectin is a polypeptide hormone, secreted exclusively by adipose tissue of the mammals. It is also known as Acrp30, AdipoQ, apM1 or GBP28, was originally identified by Scherer in 1995. It has similar and complementary action to leptin, and may have a role in reducing metabolic derangements that cause diabetes, obesity, and non-alcoholic fatty liver disease. Its mechanism of action, active forms, receptors and signaling pathways are not completely defined but seem to involve AMP-activated kinase (AMPK) and downstream acetyl-CoA carboxylase. We have identified the full length cDNA encoding mammalian AdipoR homolog (Liv-AdipoR) from the white-leg shrimp, Litopenaeus vannamei, by the next generation sequencing and bioinformatics analysis. The full length Liv-AdipoR (1245 bp) encoded a protein with 415 amino acid residues. Liv-adipoR has high similarity to AdipoR from insects. Liv-AdipR exhibited the conserved 7 transmembrane domains (7 TMs). Tissue distribution and its expressional responses also measured during molting and feeding cycles by qPCR. The mRNA expression was higher in hemocyte, hepatopancreas, gonad and muscle, followed by thoracic ganglia and heart tissue. To determine the effects of dsRNA in L. vannamei, adiponectin receptor genes, the level of transcripts were measured, after 72 hours of 10pmol dsRNA injection, the transcription level in hepatopancreas, thoracic muscle and flexor muscle showed 74%, 80% and 52% down-regulation respectively. In case of 50pmol dsRNA experiments, transcript was up-regulated in hepatopancreas; whereas in thoracic muscle and flexor muscle, it was highly down-regulated at almost 97% and 93% respectively. We identified that chronic effects of Liv-AdipoR dsRNA injection was considerably different from those in mammals, suggests that its physiological functions may be different from mammalian adiponectin receptors gene.