Zurovec M, Kodrík D, Yang C, Sehnal F, Scheller K
Institute of Entomology, Academy of Sciences, and Faculty of Biological Sciences, University of South Bohemia, Ceské Budejovice, Czech Republic.
Mol Gen Genet. 1998 Feb;257(3):264-70. doi: 10.1007/s004380050647.
The water-insoluble core of lepidopteran silk is composed of four major proteins, but only three genes have been identified. This study demonstrates that the 29- and 30-kDa components of Galleria mellonella silk are derived from a single gene designated P25. The gene is expressed exclusively in the posterior section of the silk glands as a 2-kb mRNA, which accumulates in the feeding larvae and declines at molting. The mRNA encodes a peptide of 24,864 Da that exhibits 51% identity with the putative product of the P25 gene of Bombyx. The conservation of several amino acid stretches, including the relative positions of all 8 cysteines in the mature polypeptide, implies that the P25 proteins play similar, and apparently significant roles in silk formation in the two species. A Galleria P25 cDNA yields a peptide of about 25 kDa when translated in vitro; the 29- and 30-kDa forms present in the silk are derived from this primary translation product by differential glycosylation.
鳞翅目昆虫丝的水不溶性核心由四种主要蛋白质组成，但仅鉴定出三个基因。本研究表明，大蜡螟丝的29 kDa和30 kDa组分源自单个名为P25的基因。该基因仅在丝腺后部作为2 kb的mRNA表达，其在取食幼虫中积累并在蜕皮时下降。该mRNA编码一个24,864 Da的肽，与家蚕P25基因的推定产物具有51%的同一性。几个氨基酸序列的保守性，包括成熟多肽中所有8个半胱氨酸的相对位置，表明P25蛋白在这两个物种的丝形成中发挥相似且明显重要的作用。当大蜡螟P25 cDNA在体外翻译时，产生一个约25 kDa的肽；丝中存在的29 kDa和30 kDa形式是该初级翻译产物通过差异糖基化形成的。
