Specific distribution of expression and enzymatic activity of cholesterol biosynthetic enzyme DHCR24 orthologs in the phytophagous insect
Specific distribution of expression and enzymatic activity of cholesterol biosynthetic enzyme DHCR24 orthologs in the phytophagous insect
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DOI：
10.1080/09168451.2019.1667221
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发表时间：
2019-09-22
影响因子：
1.6
通讯作者：
Nagata, Shinji
中科院分区：
文献类型：
--
作者：
Fujimori, Haruna;Zhou, Yi Jun;Nagata, Shinji
昆虫必须摄入类固醇化合物，因为它们不能从头合成胆固醇。在植食性昆虫中，在24-脱氢胆固醇还原酶的作用下，植物甾醇的酶促转化为胆固醇，从而获得胆固醇。在此，我们报道了家蚕中存在两个DHRE24同源物，BmDHCR24-1和-2，以及几个转录本变体。与RT-PCR的空间表达分析结果一致，该基因在家蚕幼虫中肠组织中具有较强的酶活性，而在所研究的其他组织中活性较弱。此外，BmDHCR24-1在HEK293细胞中的表达具有酶活性，而BmDHCR24-2则不具有活性，尽管这两个BmDHCR24都定位在哺乳动物的内质网中，以发挥其酶活性。目前的数据表明，在植食性鳞翅目昆虫幼虫的中肠中，BmDHCR24-1而不是BmDHCR24-2促进了植物甾醇向胆固醇的转化。
Insects must intake sterol compounds because of their inability to synthesize cholesterol de novo. In phytophagous insects, enzymatic conversion of phytosterols to cholesterol involving 24-dehydrocholesterol reductase (DHCR24) exerts to acquire cholesterol. Here, we reported the presence of two DHCR24 homologs in the silkworm Bombyx mori, BmDHCR24-1 and -2, with several transcript variants. Consistent with the data of spatial expression analyses by RT-PCR, predominant enzymatic activity of DHCR24 was observed in B. mori larval midgut whereas weak activity was observed in the other tissues examined. In addition, BmDHCR24-1 expression in HEK293 cells showed an enzymatic activity, but BmDHCR24-2 did not, although both BmDHCR24s were localized in the endoplasmic reticulum, where the mammalian DHCR24s are located to exert their enzymatic activities. The present data indicated that BmDHCR24-1 but not BmDHCR24-2 contributes to conversion of phytosterols to cholesterol mainly in the midgut of the phytophagous lepidopteran larvae.