Cabrera Ana R, Donohue Kevin V, Khalil Sayed M S, Sonenshine Daniel E, Roe R Michael
North Carolina State University, Department of Entomology, Campus Box 7613, Raleigh, NC 27695, USA.
J Insect Physiol. 2009 Jul;55(7):655-61. doi: 10.1016/j.jinsphys.2009.04.006. Epub 2009 May 3.
In mites, vitellogenin synthesis, regulation and uptake by the oocytes as vitellin remain practically unknown. Although a partial sequence of the gene is now available, no previous studies have been conducted that describe the native vitellin protein in mites. The objective of this study was to characterize vitellin in the twospotted spider mite, Tetranychus urticae. The native twospotted spider mite vitellin migrated as a single major band with a molecular weight of 476+/-14.5 kDa as compared to 590+/-25.5 kDa for vitellin from the American dog tick, Dermacentor variabilis. However, isoelectric focusing analysis of native spider mite vitellin showed five bands with pI values slightly acidic to neutral (pH 5.8, 6.2, 6.7, 7.0 and 7.2), as is the case for insect and tick vitellins. Reducing conditions (SDS-PAGE) also revealed multiple subunits ranging from 290.9 to 3.6 kDa and was similar to that found in D. variabilis. Spider mite vitellin weakly bound lipids and carbohydrates compared to the tick. Unlike D. variabilis, the spider mite egg yolk protein does not bind heme. The significance of non-heme binding in mites is discussed.
在螨类中，卵黄原蛋白的合成、调控以及被卵母细胞摄取形成卵黄蛋白的过程实际上仍不清楚。尽管该基因的部分序列现已可得，但此前尚未有研究描述螨类中的天然卵黄蛋白。本研究的目的是对二斑叶螨（Tetranychus urticae）的卵黄蛋白进行表征。与美洲犬蜱（Dermacentor variabilis）的卵黄蛋白分子量为590±25.5 kDa相比，二斑叶螨的天然卵黄蛋白迁移为一条单一的主要条带，分子量为476±14.5 kDa。然而，对二斑叶螨天然卵黄蛋白的等电聚焦分析显示有五条带，其pI值略呈酸性至中性（pH 5.8、6.2、6.7、7.0和7.2），昆虫和蜱的卵黄蛋白也是如此。还原条件下（SDS-PAGE）也揭示了多个亚基，分子量范围从290.9 kDa到3.6 kDa，这与在美洲犬蜱中发现的情况相似。与蜱相比，二斑叶螨的卵黄蛋白与脂质和碳水化合物的结合较弱。与美洲犬蜱不同，二斑叶螨的蛋黄蛋白不结合血红素。文中讨论了螨类中不结合血红素的意义。
