Furins are a family of proteases involved in the processing of many proproteins including growth regulators, immune proteins, and toxins. However, very few studies have been conducted on furin-like PCs in insects. Herein, we isolated and characterized full-length furin-like cDNAs (Psfurin-1 and Psfurin-2) from larvae of Protaetia brevitarsis seulensis (Kolbe). To search for furin-like PC cDNAs, we used high-throughput RNA sequencing (RNA-seq) expression profiling of data. The Psfurin-1 and Psfurin-2 transcripts, 2,370 and 3,702 nucleotides in length, respectively, encode peptides of 790 and 1,234 amino acids with calculated molecular masses of 88.3 and 135.6 kDa. We identified a consensus site for proprotein convertase that includes Asp, His, Asn, and Ser catalytic residues, and revealed the presence of a subtilisin-like serine protease/putative cell envelope proteinase domain related to the immune system. The predicted structures of the two proteins are very similar, but the cell envelope protease/immune-related domain differs somewhat. To examine the possible immune-related expression of Psfurin-1 and 2 transcripts, late larvae were injected with the Gram-negative bacterium Escherichia coli or the yeast Saccharomyces cerevisiae. Expression of Psfurin-1 mRNA in E. coli K12-challenged larvae was ~15-fold higher at 8 h and ~20-fold higher at 12 h than in LB medium-challenged control larvae. In the case of yeast-challenged larvae, expression of Psfurin-1 mRNA was not as elevated as in E. coli K12-challenged larvae, but expression was 4–5-fold higher than in LB medium-challenged larvae. Expression of Psfurin-2 mRNA in E. coli K12-challenged and yeast-challenged larvae was also significantly higher than in LB medium-challenged controls from 4 to 48 h, but expression levels were lower than for Psfurin-1 mRNA in both E. coli K12- and yeast-challenged larvae.

弗林蛋白酶是一个蛋白酶家族，涉及许多前蛋白的加工，包括生长调节剂、免疫蛋白和毒素。然而，很少有关于昆虫中类似弗林蛋白酶的 PC 的研究。在此，我们从Protaetia brevitarsis seulensis (Kolbe) 的幼虫中分离并表征了全长弗林蛋白酶样 cDNA（Psfurin-1和Psfurin-2）。为了搜索类似弗林蛋白酶的PC cDNA，我们使用了高通量 RNA 测序 (RNA-seq) 数据表达谱。所述Psfurin-1和Psfurin-2转录本的长度分别为 2,370 和 3,702 个核苷酸，编码 790 和 1,234 个氨基酸的肽，计算分子量为 88.3 和 135.6 kDa。我们确定了前蛋白转化酶的共有位点，包括 Asp、His、Asn 和 Ser 催化残基，并揭示了与免疫系统相关的枯草杆菌蛋白酶样丝氨酸蛋白酶/假定细胞包膜蛋白酶域的存在。两种蛋白质的预测结构非常相似，但细胞包膜蛋白酶/免疫相关结构域略有不同。为了检查Psfurin-1和2转录本可能与免疫相关的表达，晚期幼虫被注射革兰氏阴性细菌大肠杆菌或酵母酿酒酵母. 的表达Psfurin-1 mRNA表达的大肠杆菌K12激发的幼虫在8小时〜15倍高的和在〜12小时比在LB培养基中攻击的对照幼虫20倍。在酵母攻击的幼虫的情况下，Psfurin-1 mRNA 的表达不像大肠杆菌K12 攻击的幼虫那样升高，但表达量比 LB 培养基攻击的幼虫高 4-5 倍。从 4 到 48 小时，大肠杆菌K12 攻击和酵母攻击幼虫中Psfurin-2 mRNA 的表达也显着高于 LB 培养基攻击对照，但表达水平低于Psfurin-1 mRNA 。大肠杆菌K12 和酵母攻击的幼虫。