Molecular cloning and characterization of porcine ribosomal protein L21

Insights into the DNA methylation of Portunus trituberculatus in response to Vibrio parahaemolyticus infection

Vibrio parahaemolyticus is the main pathogen causing acute hepatopancreatic necrotic disease in crustaceans. To elucidate the epigenetic regulatory mechanism of crustacean resistance to V. parahaemolyticus infection, we conducted artificial infection studies on Portunus trituberculatus. The results showed that the mortality rate reached the highest at 12 h of artificial infection, which was 23.69 %. At 72 h after V parahaemolyticus infection, the expression level of DNA demethylase (ten-eleven-translocation protein) Tet was significantly decreased, the expression of DNA methyltransferase Dnmt3B fluctuated significantly. Based on the differential expression levels of Tet and Dnmt3B. We depict for DNA methylation profiles of the whole genome of P. trituberculatus at single-base resolution by using whole-genome bisulfite sequencing (WGBS) on hemolymph tissues. The overall DNA methylation level was low at 2.16 % in P. trituberculatus hemolymph. A total of 2590 differentially methylated regions (DMRs) were identified, of which 1329 were hypermethylated and 1261 were hypomethylated, and 1389 genes were annotated in these DMRs. Differently methylated genes (DMGs) were significantly enriched in ribosomes (KO03010), protein kinases (KO01001), cell cycle (HSA04110), endocrine resistance (HSA01522) and FoxO signaling pathway (KO04068). Finally, we selected six differentially methylated genes for quantitative analysis. The results showed that DNA methylation not only has a negative regulatory effect on gene expression, but also has a positive regulatory effect. These results indicated that DNA methylation in the regulation of genes involved in immune responses contributes to the resistance of P. trituberculatus to V. parahaemolyticus, which is valuable for understanding how crustaceans regulate the innate immune system to defend against bacterial infections.

Integrative transcriptomic analysis reveals a broad range of toxic effects of triclosan on coral Porites lutea

Triclosan (TCS) is an antimicrobial agent commonly used in personal care products. However, little is known about its toxicity to corals. Here, we examined the acute toxic effects (96 h) of TCS at different levels to the coral Porites lutea. Results showed that the bioaccumulation factors (BAFs) of TCS in Porites lutea decreased with increasing TCS exposure levels. Exposure to TCS at the level up to 100 μg/L did not induce bleaching of Porites lutea. However, by the end of the experiment, both the density and chlorophyll a content of the symbiotic zooxanthellae were 19-52 % and 19.9-45.6 % lower in the TCS treatment groups than in the control, respectively. For the coral host, its total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and catalase (CAT) activities were all significantly lower in the TCS treatment groups than the control. Transcriptome analysis showed that 942 and 1077 differentially expressed genes (DEGs) were identified in the coral host in the 0.5 and 100 μg/L TCS treatment groups, respectively. Meanwhile, TCS can interfere with pathways related to immune system and reproductive system in coral host. Overall, our results suggest that environmentally relevant concentrations of TCS can impact both the coral host and the symbiotic zooxanthellae.

Protein Lysine Methyltransferase SMYD2: A Promising Small Molecule Target for Cancer Therapy

In epigenetic research, the abnormality of protein methylation modification is closely related to the occurrence and development of tumors, which stimulates the interest of researchers in protein methyltransferase research and the efforts to develop corresponding specific small molecule inhibitors. Currently, the protein lysine methyltransferase SMYD2 has been identified as a promising new small molecule target for cancer therapy. But its biological functions have not been fully studied and relatively few inhibitors have been reported, thus this field needs to be further explored. This perspective provides a comprehensive and systematic review of the available resources in this field, including its research status, biological structure, related substrates and methylation mechanisms, and research status of inhibitors. In addition, this perspective elaborates in detail the current challenges in this field, our insights into what needs to be done next, rational drug design of novel SMYD2 inhibitors, and foreseeable development directions in the future.

Select Porcine Elongation Factor 1α Sequences Mediate Stable High-Level and Upregulated Expression of Heterologous Genes in Porcine Cells in Response to Primate Serum

Genetically engineered (GE) pigs with various combinations of genetic profiles have been developed using heterologous promoters. This study aimed to identify autologous promoters for high and ubiquitous expression of xenotransplantation relevant genes in GE pigs. A 1.4 kb upstream regulatory sequence of porcine elongation factor 1α (pEF1α) gene was selected and isolated for use as a promoter. Activity of the pEF1α promoter was subsequently compared with that of the cytomegalovirus (CMV) promoter, CMV enhancer/chicken β-actin (CAG) promoter, and human EF1α (hEF1α) promoter in different types of pig-derived cells. Comparative analysis of luciferase and mutant human leukocyte antigen class E-F2A-β-2 microglobulin (HLA-E) expression driven by pEF1α, CMV, CAG, and hEF1α promoters revealed the pEF1α promoter mediated comparable expression levels with those of the CAG promoter in porcine ear skin fibroblasts (PEFs) and porcine kidney-15 (PK-15) cells, but lower than those of the CAG promoter in porcine aortic endothelial cells (PAECs). The pEF1α promoter provided long-term stable HLA-E expression in PEFs, but the CAG promoter failed to sustain those levels of expression. For xenogeneic serum-induced cytotoxicity assays, the cells were cultured for several hours in growth medium supplemented with primate serum. Notably, the pEF1α promoter induced significant increases in luciferase and HLA-E expression in response to primate serum in PAECs compared with those driven by the CAG promoter, suggesting the pEF1α promoter could regulate temporal expression of heterologous genes under xenogeneic-cytotoxic conditions. These results suggest the pEF1α promoter may be valuable for development of GE pigs spatiotemporally and stably expressing immunomodulatory genes for xenotransplantation.

The ribosomal protein eL21 interacts with the protein lysine methyltransferase SMYD2 and regulates its steady state levels

The protein lysine methyltransferase, SMYD2 is involved in diverse cellular events by regulating protein functions through lysine methylation. Though several substrate proteins of SMYD2 are well-studied, only a limited number of its interaction partners have been identified and characterized. Here, we performed a yeast two-hybrid screening of SMYD2 and found that the ribosomal protein, eL21 could interact with SMYD2. SMYD2-eL21 interaction in the human cells was confirmed by immunoprecipitation methods. In vitro pull-down assays revealed that SMYD2 interacts with eL21 directly through its SET and MYND domain. Computational mapping, followed by experimental studies identified that Lys81 and Lys83 residues of eL21 are important for the SMYD2-eL21 interaction. Evolutionary analysis showed that these residues might have co-evolved with the emergence of SMYD2. We found that eL21 regulates the steady state levels of SMYD2 by promoting its transcription and inhibiting its proteasomal degradation. Importantly, SMYD2-eL21 interaction plays an important role in regulating cell proliferation and its dysregulation might lead to tumorigenesis. Our findings highlight a novel extra-ribosomal function of eL21 on regulating SMYD2 levels and imply that ribosomal proteins might regulate wide range of cellular functions through protein-protein interactions in addition to their core function in translation.