Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania 'Luigi Vanvitelli', 81100 Caserta, Italy.
Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, 20133 Milan, Italy.
Int J Mol Sci. 2020 Sep 28;21(19):7158. doi: 10.3390/ijms21197158.
The edible mushroom produces a ribotoxin-like protein known as Ageritin. In this work, the gene encoding Ageritin was characterized by sequence analysis. It contains several typical features of fungal genes such as three short introns (60, 55 and 69 bp) located at the 5' region of the coding sequence and typical splice junctions. This sequence codes for a precursor of 156 amino acids (~17-kDa) containing an additional -terminal peptide of 21 amino acid residues, absent in the purified toxin (135 amino acid residues; ~15-kDa). The presence of 17-kDa and 15-kDa forms was investigated by Western blot in specific parts of fruiting body and in mycelia of . Data show that the 15-kDa Ageritin is the only form retrieved in the fruiting body and the principal form in mycelium. The immunolocalization by confocal laser scanning microscopy and transmission electron microscopy proves that Ageritin has vacuolar localization in hyphae. Coupling these data with a bioinformatics approach, we suggest that the -terminal peptide of Ageritin (not found in the purified toxin) is a new signal peptide in fungi involved in intracellular routing from endoplasmic reticulum to vacuole, necessary for self-defense of ribosomes from Ageritin toxicity.
可食用蘑菇产生一种类似于核糖体毒素的蛋白，称为 Ageritin。在这项工作中，通过序列分析对编码 Ageritin 的基因进行了表征。它包含真菌基因的几个典型特征，如位于编码序列 5' 区的三个短内含子（60、55 和 69bp）和典型的剪接接头。该序列编码一个 156 个氨基酸（17kDa）的前体，其中包含一个在纯化毒素中不存在的额外的 - 端肽 21 个氨基酸残基（135 个氨基酸残基；15kDa）。通过 Western blot 在特定的子实体部分和 的菌丝体中研究了 17kDa 和 15kDa 形式的存在。数据表明，15kDa 的 Ageritin 是在子实体中检索到的唯一形式，也是菌丝体中的主要形式。通过共聚焦激光扫描显微镜和透射电子显微镜进行的免疫定位证明，Ageritin 在菌丝体中具有液泡定位。将这些数据与生物信息学方法相结合，我们认为 Ageritin 的 - 端肽（在纯化毒素中未发现）是真菌中一种新的信号肽，参与从内质网到液泡的细胞内路由，这对于核糖体免受 Ageritin 毒性的自我防御是必要的。
