Comparative Transcriptome Analysis Identifies MAPK Signaling Pathway Associated with Regulating Ovarian Lipid Metabolism during Vitellogenesis in the Mud Crab, Scylla paramamosain

Abstract

The mud crab, Scylla paramamosain, has abundant nutrients in the ovary, where numerous lipids accumulate during ovarian maturation. However, the mechanism behind the accumulation of lipids in the ovary of mud crab during ovarian maturation is largely unknown. This study conducted a comparative transcriptome analysis of the ovaries of mud crabs at various stages of ovarian maturation. A total of 63.69 Gb of clean data was obtained, with a Q30 of 93.34%, and 81,893 unigenes were identified, including 10,996 differentially expressed genes (DEGs). After KEGG enrichment of these DEGs, MAPK signaling pathway was significantly enriched during vitellogenesis. Moreover, the expression levels of genes involved in carbohydrate, amino acid, and lipid metabolism were found to be higher during vitellogenesis. The two genes (Sp-Eip75B and Sp-Eip78C) that are homologous to the vertebrate gene PPARγ in the PPAR signaling pathway, were identified. Additionally, genes in MAPK signaling pathway might regulate lipid metabolism through PPAR signaling pathway based on Protein-Protein Interaction (PPI) network. These findings suggest that MAPK signaling pathway plays a critical role in lipid metabolism in the ovary during vitellogenesis, which provides new insights into the mechanism of lipid accumulation during ovarian maturation in mud crabs.

Temporal and Spatial Signatures of Scylla paramamosain Transcriptome Reveal Mechanistic Insights into Endogenous Ovarian Maturation under Risk of Starvation

“…The histology results were then interpreted. A previous study confirmed all mud crabs immediately after hatching were at the same starting point of the early vitellogenesis stage (stage III, ovarian color light-yellow) [53]. The ovarian stages in our study were distinguished as the early vitellogenesis stage (stage III, light-yellow) and the late vitellogenesis stage (stage IV, orange) [54,55], as confirmed by both morphology and histology.…”

“…A pea-sized piece of each tissue was transferred to Bonn fixation for about 24 h and then washed with 70% alcohol three times before putting it into 70% alcohol for −20 • C preservation. Paraffin slices were stained and dehydrated as previously described [53]. The histology results were then interpreted.…”

“…A total of 0.2 g of each sample was hydrolyzed and made into derivatives, as previously described [53]. A total of 0.45 mL of mobile phase A, consisting of 0.1 mol/L anhydrous sodium acetate and acetonitrile, was added, mixed well, and passed through the membrane.…”

“…To characterize the starvation response at the molecular level, all 24 samples were used for RNA-seq as previously described [53]. Quality inspection and quantification of products using Qubit fluorescence quantification/enzyme labeling instruments ensured that the RNA samples were subjected to quality control in three aspects: total quantity, purity, and completeness.…”

Transcriptome profiling reveals that differences in regulatory patterns of gonad development between male and female largemouth bass (Micropterus salmoides) contribute to dimorphic weight gain

“…The upregulation of lrp8 and lrp13 expression promoted intracellular yolk granule formation in stage IV oocytes [8]. Enhanced expression of genes in the MAPK signaling pathway was found to activate the PPAR signaling pathway via protein-protein interactions, thereby regulating lipid metabolism and facilitating oocyte development [9].…”