Quantitative Proteome Reveals Variation in the Condition Factor of Sea Urchin Strongylocentrotus nudus during the Fishing Season Using an iTRAQ-based Approach

To investigate the variation in the condition factor of the sea urchin Strongylocentrotus nudus (S. nudus), gonads were collected in May (MAY), June (JUN), and July (JUL), at the beginning (AUG-b) and end of August (AUG-e). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) detection of the gonads revealed an obvious enhancement of the band at about 37 kDa from July, which was identified as transforming growth factor-beta-induced protein ig-h3 (TGFBI) by nanoLC-ESI-MS/MS. Gonadal proteins were identified by isobaric tagging for relative and absolute quantitation (iTRAQ), and regulation of the identified proteins in pairs of the collected groups was observed. A total of 174 differentially expressed proteins (DEPs) were identified. Seven of the DEPs showed significant correlations with both the gonad index (GI) and protein content. These correlations included 6-phosphogluconate dehydrogenase, decarboxylating isoform X2 (6PGD), CAD protein, myoferlin isoform X8, ribosomal protein L36 (RL36), isocitrate dehydrogenase [NADP], mitochondrial isoform X2 (IDH), multifunctional protein ADE2 isoform X3, sperm-activating peptides (SAPs) and aldehyde dehydrogenase, and mitochondrial (ALDH). However, TGFBI had no correlation with gonad index (GI) or protein content. 6PGD, IDH, multifunctional protein ADE2 isoform X3, and ALDH were shown to interact with each other and might play key roles in changing the condition factor of S. nudus gonads.

Identification, expression analysis, and the regulating function on C/EBPs of KLF10 in Dalian purple sea urchin, Strongylocentrotus nudus

Accumulating evidence indicates that Krüppel-like factors (KLFs) play important roles in fat biology via the regulation of CCAAT/enhancer binding proteins (C/EBPs). However, KLFs and C/EBPs have not been identified from Strongylocentrotus nudus, and their roles in this species are not clear. In this study, the full-length cDNA of S. nudus KLF10 (SnKLF10) and three cDNA fragments of S. nudus C/EBPs (SnC/EBPs) were obtained. Examination of tissue distribution and expression patterns during gonadal development implied that SnKLF10 and SnC/EBPs play important roles in gonadal lipogenesis. The presence of transcription factor-binding sites (TFBSs) for KLFs in SnC/EBPs, and the results of an over-expression assay, revealed that SnKLF10 negatively regulates the transcription of SnC/EBPs. In addition, the core promoter regions of SnC/EBPs were determined, and multiple TFBSs for transcription factor (TFs) were identified, which are potential regulators of SnC/EBP transcription. Taken together, these results suggest that SnC/EBP genes are potential targets of SnKLF10, and that SnKLF10 plays a role in lipogenesis by repressing the transcription of SnC/EBPs. These findings provide information for further studies of KLF10 in invertebrates and provide new insight into the regulatory mechanisms of C/EBP transcription.