The Japanese rhinoceros beetle (Trypoxylus dichotomus [Allomyrina dichotoma]) produces the lectins allo A-I and allo A-II, which have strong N-acetyllactosamine (Galβ1-4GlcNAc)-binding activity. It has been suggested that the two lectins are formed from three subunits (α, β, and γ), with allo A-I comprising α and γ subunits and allo A-II comprising β and γ subunits. Here, we determined the cDNA sequences of these subunits using both conventional polymerase chain reaction (PCR)-cloning-sequencing and transcriptome-sequencing analyses. For the α and β subunits, one gene (locus) for each was predicted, whereas for the γ subunit, two types of cDNA sequences were obtained, which we named γ1 and γ2. These two types probably have distinct loci. Average nucleotide sequence identities among the subunits ranged from 87.6% (between α and γ1) to 92.6% (between γ1 and γ2), suggesting that they form a gene family. Although no homology was found between the sequences of allo A and other known lectin proteins in a protein database search, some unknown proteins containing the DUF3421 domain were identified. Those DUF3421 domain-encoding proteins are upregulated in the insect larval midgut. Thus, we infer that allo A genes also play an important role in larvae and that their lectin activity may have been obtained collaterally.

日本犀牛甲虫（Trypoxylus dichotomus [ Allomyrina dichotoma ]）产生具有强N的凝集素 allo AI 和 allo A-II-乙酰乳糖胺（Galβ1-4GlcNAc）结合活性。有人提出这两种凝集素由三个亚基（α、β 和 γ）形成，allo AI 包含 α 和 γ 亚基，allo A-II 包含 β 和 γ 亚基。在这里，我们使用常规聚合酶链反应 (PCR)-克隆-测序和转录组测序分析确定了这些亚基的 cDNA 序列。对于 α 和 β 亚基，预测了每个基因（基因座），而对于 γ 亚基，获得了两种类型的 cDNA 序列，我们将其命名为 γ1 和 γ2。这两种类型可能具有不同的基因座。亚基之间的平均核苷酸序列同一性范围为 87.6%（在 α 和 γ1 之间）到 92.6%（在 γ1 和 γ2 之间），表明它们形成了一个基因家族。虽然在蛋白质数据库搜索中未发现 allo A 和其他已知凝集素蛋白质的序列之间存在同源性，但鉴定出一些含有 DUF3421 结构域的未知蛋白质。那些 DUF3421 结构域编码蛋白在昆虫幼虫中肠中上调。因此，我们推断allo A基因在幼虫中也起重要作用，并且它们的凝集素活性可能是附带获得的。