Molecular characterization of gonad‐inhibiting hormone of Penaeus monodon and elucidation of its inhibitory role in vitellogenin expression by RNA interference

Abstract

One of the important peptide hormones that control reproduction in crustaceans is gonad‐inhibiting hormone (GIH). GIH is known to modulate gonad maturation by inhibiting synthesis of vitellogenin (Vg), the precursor of yolk proteins. In this study, a cDNA encoding a GIH (Pem‐GIH) from the eyestalk of Penaeus monodon was cloned using RT‐PCR and RACE techniques. Pem‐GIH cDNA is 861 bp in size with a single ORF of 288 bp. The deduced Pem‐GIH consists of a 17‐residue signal peptide and a mature peptide region of 79 amino acids with features typical of type II peptide hormones from the CHH family. Pem‐GIH transcript was detected in eyestalk, brain, thoracic and abdominal nerve cords of adult P. monodon. The gonad‐inhibiting activity of Pem‐GIH was investigated using the RNA interference technique. Double‐stranded RNA, corresponding to the mature Pem‐GIH sequence, can trigger a decrease in Pem‐GIH transcript levels both in eyestalk ganglia and abdominal nerve cord explant culture and in female P. monodon broodstock. The conspicuous increase in Vg transcript level in the ovary of GIH‐knockdown shrimp suggests a negative influence for Pem‐GIH on Vg gene expression, and thus implies its role as a gonad‐inhibiting hormone. This is the first report to demonstrate the use of double‐stranded RNA to elucidate the function of GIH in P. monodon.

Reproductive regulators in decapod crustaceans: an overview

“…Alternative techniques have been attempted to stimulate ovarian development, such as administration of gonad inhibitory hormone (GIH) antibody, hormonal level changes by environmental factors such as temperature, salinity and photoperiod, precise functionality of neurotransmitters and double-stranded RNA interference (dsRNAi) to reduce gonad inhibitory peptide transcript. The results from these experiments have revealed the potential (Chang et al, 2001;FanjulMoles, 2006;Mazurová et al, 2008;Nagaraju, 2007;Nagaraju and Borst, 2008;Treerattrakool et al, 2008) to stimulate gonad maturity. So, in this context, I will discuss up-to-date research on gonad regulatory factors and their role in reproductive development.…”

“…Double-stranded RNA, related to the mature Pem-VIH sequence, can elicit a decrease in Penaeus monodon-VIH (Pem-VIH) transcript levels in both eyestalk ganglia and abdominal nerve cord explants culture and in female P. monodon broodstock. The prominent increase in vitellogenin (Vg) transcript level in the ovary of VIH-knockdown shrimp suggests a negative influence of Pem-VIH on Vg gene expression, and thus implies its role as a VIH (Treerattrakool et al, 2008). …”

Penaeus monodon is protected against gill- associated virus by muscle injection but not oral delivery of bacterially expressed dsRNAs

“…The existence of this RNAi machinery is thus being exploited widely to determine gene functions in shrimp. Due to its ability to specifically target and degrade endogenous mRNAs, the RNAi response is being investigated as a means of down-regulating the expression of genes that might, for example, promote spawning (Lugo et al 2006, Tiu and Chan 2007, Treerattrakool et al 2008, direct traits such as gender (Sellars 2007, Tiu et al 2008 and modulate the rate of haemolymph clotting (Maningas et al 2008). As in many other organisms, the RNAi response mechanism of shrimp is also capturing research attention as a means of interfering with the ABSTRACT: Gill-associated virus (GAV) is a nidovirus that commonly infects Penaeus monodon (black tiger shrimp) in eastern Australia, causing morbidity and mortalities in the acute stage of disease.…”

The Optimum Dose of Thyroxine Hormone Supplementation in Broodstock Mud Crab (Scylla Serrata) to Accelerate Ovarian Maturation

“…Vitellogenesis is an important step in the maturation of the ovary. Vitellogenin can be synthesized in the ovarium and other nonovarian organs such as hepatopancreas [9].…”