Induction of Ovarian Maturation in Penaeus monodon by Molecular Signal Interventional Approach

Abstract

Vitellogenin (VTG) synthesis in the hepatopancreas and ovary is negatively regulated by vitellogenesis-inhibiting hormone (VIH) produced in the neurosecretory cell of X-organ/sinus gland complex of the eyestalks of penaeid shrimp. Eyestalk ablation is used commercially to induce ovarian maturation in shrimps which leads to an eventual loss of the spawner. The aim of the present study was to understand the molecular mechanism of VIH regulation in ovarian development and its inhibition of VTG gene expression by using a MEK-specific inhibitor (U0126). The real-time quantitative PCR results showed VTG mRNA level was progressively increased in the ovary and hepatopancreas of unilateral eyestalk-ablated and inhibitor-treated shrimps. Western blot analysis also showed that phosphoMEK was detected only in the unilateral eyestalk-ablated and control shrimp, whereas phospho-MEK was not detected in inhibitor-treated shrimp. DAX-1, SF-1, and StAR expression correlated with changes in VIH mRNA and altered phospho-ERK levels. This is consistent with the hypothesis that suppression of DAX-1 results in SF-1-mediated StAR protein upregulation of estradiol that is implicated in vitellogenesis. This is the first report that demonstrates the molecular mechanism of VIH suppression via MEK pathway to induce ovarian maturation in female Penaeus monodon by molecular signal intervention, a less-invasive method than traditional eyestalk ablation.

Characterization, expression, and function analysis of gonad-inhibiting hormone in Oriental River prawn, Macrobrachium nipponense and its induced expression by temperature

“…Taken results of previous crustacean's studies together, GIH acts on the ovary tissue involved in vitellogenesis synthesis and eyestalk ablation can induce ovary maturation of by diminishing GIH production (De Kleijn et al, 1994;Ohira et al, 2006;Treerattrakool et al, 2008;Devaraj et al, 2012;Hopkins, 2012). Accordingly, we investigated the transcriptional profile of Mn-GIH during ovary stages in both eyestalk and ovary.…”

“…The RNAi effect had variation between two species and also provides further background information on the use of dsRNA for other reproductive related gene functions. Crustacean ovary maturation is regulated by an endogenous and exogenous complex network of interactions (Devaraj et al, 2012). Environmental factors, such as temperature, photoperiod and food availability, all influence ovary maturation (Adiyodi and Adiyodi, 1970).…”

“…This hormone family is known as the crustacean hyperglycemic hormone family (CHH family) (Spanings-Pierrot et al, 2000;Katayama et al, 2001;Watson et al, 2001;Webster et al, 2012). It was well known for playing an important role in regulating reproduction by inhibiting vitellogenesis (VG) synthesis (De Kleijn et al, 1994;Treerattrakool et al, 2008;Devaraj et al, 2012). In decapod crustaceans, GIH was first isolated and characterized in the eyestalk extracts of Homarus americanus (Soyez et al, 1987) and then was studied in other a few species such as Macrobrachium rosenbergii, Nephrops norvegicus, Penaeus monodon, and Litopenaeus vannamei (Yang and Rao, 2001;Edomi et al, 2002;Ohira et al, 2006;Treerattrakool et al, 2008;Hopkins, 2012;Chen et al, 2014).…”

Identification of MicroRNAs and Their Target Genes Associated with Ovarian Development in Black Tiger Shrimp (Penaeus monodon) Using High-Throughput Sequencing

“…In total, 84 target genes were mapped to the four pathways (Supplementary Table S5 ); some of these genes had already been shown to be involved in the process of ovarian development in other organisms (Table 6 ). For example, the catalytic and regulatory subunits of mitogen-activated protein kinase kinase ( MAPKK ) 25 , extracellular signal-regulated kinase (ERK) 26 , 27 , fatty acid synthase ( FAS ) 28 , 29 , cyclin A, cyclin B 30 – 34 , and 14-3-3-like protein (14-3-3-like) 35 , 36 were previously shown to be involved.…”

Modulation of complex coordinated molecular signaling by 5HT and a cocktail of inhibitors leads to ovarian maturation of Penaeus monodon in captivity

“…Thus, ablation of eyestalk restricts the availability of VIH and promotes vitellogenesis (Benzie, ). In an attempt to identify a noninvasive or minimal method to induce ovarian maturation, a similar condition was mimicked with the use of inhibitor U0I26, that inhibited mitogen‐activated protein kinase kinase (MEK) and decreased the levels of VIH, thus accelerating the early oocyte maturation (Devaraj & Natarajan, ; Devaraj, Saravanakumar, & Thiyagu, ; Imayavaramban, Dhayaparan, & Devaraj, ).…”