Abstract
Eyestalk ablation is the most common method to induce ovarian maturation in decapod crustacean aquaculture, but it jeopardizes broodstock survival and larvae production. It is important to understand the molecular basis underlying the maturation triggered by ablation and thereby develop an alternative measure for maturation manipulation. In this study, we investigate alterations of ovarian proteome and miRNA profile after ablation in a commercially important marine crab Portunus trituberculatus. Quantitative proteomic analysis using iTRAQ reveals that 163 proteins are differentially expressed following ablation, and modulation of methyl farnesoate metabolism and activation of calcium signaling may play important roles in the ovarian maturation induced by ablation. miRNA expression profiling identifies 31 miRNAs that show statistically significant changes. Integration of miRNA and proteome expression data with miRNA target prediction algorithms generates a potential regulatory network consisting of 26 miRNAs and 30 proteins linked by 71 possible functional associations. The miRNA-protein network analysis suggests that miRNAs are involved in promoting ovarian maturation by controlling expression of proteins related to methyl farnesoate synthesis, calcium signals, and energy metabolism. Experimental validation and temporal expression analysis indicate multiple miRNAs can act synergistically to regulate expression of Farnesoic acid O-methyltransferase and Calmodulin. Our findings provide new insights for elucidating the mechanisms underlying eyestalk ablation-induced ovarian maturation and could be useful for devising an alternative technique for manipulating reproduction in P. trituberculatus and other decapods.
Highlights
The eyestalk, where the X-organ/sinus gland (XO/SG) complex is located, is an important neuroendocrine system in crustaceans, which is the major site of production and storage for a variety of important neuropeptides, such as the gonad-inhibiting hormone (GIH), the molt-inhibiting hormone (MIH), the pigmentdispersing hormone (PDH), and the red pigment-concentrating hormone (RPCH) [1, 2]
To identify proteins involved in eyestalk ablation (ESA)-induced ovarian maturation, isobaric tags for relative and absolute quantitation (iTRAQ) was employed to assess ovarian protein expression changes at the fourth day after ESA
Proteomic analysis using iTRAQ shows that 163 proteins are differentially expressed in the ovary of intact and ablated crabs, and among them, proteins regulating vitellogenesis, oocyte meiosis, and energy metabolism are identified, indicating their involvement in promoting ovarian maturation after ESA. miRNA transcriptome results show that 31 miRNAs exhibit differential expression after ESA
Summary
The eyestalk, where the X-organ/sinus gland (XO/SG) complex is located, is an important neuroendocrine system in crustaceans, which is the major site of production and storage for a variety of important neuropeptides, such as the gonad-inhibiting hormone (GIH), the molt-inhibiting hormone (MIH), the pigmentdispersing hormone (PDH), and the red pigment-concentrating hormone (RPCH) [1, 2] Among these neuropeptides, GIH is considered to play a key role in regulating female crustacean reproduction by repressing ovarian maturation and spawning [3]. Lee et al [12] report that ESA can modulate gene expression in the hepatopancreas of Litopenaeus vannamei, upregulating genes related to metabolic processes as well as those associated with immunity and stress responses These studies expand our knowledge on the transcriptional regulation that mediates ESA-induced maturation. No information is available regarding gene expression regulation at post-transcriptional and translational levels following ESA
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