TRANSFERRIN IN A COCKROACH - MOLECULAR-CLONING, CHARACTERIZATION, AND SUPPRESSION BY JUVENILE-HORMONE
TRANSFERRIN IN A COCKROACH - MOLECULAR-CLONING, CHARACTERIZATION, AND SUPPRESSION BY JUVENILE-HORMONE
复制标题
DOI：
10.1073/pnas.90.4.1320
复制
发表时间：
1993-02-15
影响因子：
11.1
通讯作者：
LAW, JH
中科院分区：
文献类型：
--
作者：
JAMROZ, RC;GASDASKA, JR;LAW, JH
在一项研究中，少年的荷尔蒙调节基因的表达，我们分离出一个匿名的cDNA代表的消息，强烈抑制保幼激素的脂肪体的蟑螂Blaberus discoidalis。从cDNA序列推导出的蛋白质序列中表现出令人信服的相似性，转铁蛋白，一个超家族的内部重复，80 kDa的铁结合/转运蛋白，其特征在于从几种脊椎动物，到目前为止，一种昆虫（烟草天蛾，天蛾）。我们从蟑螂血淋巴中分离出一个分子量为78 kDa的蛋白质，验证了它与克隆的cDNA的一致性，并发现它确实与铁结合。蟑螂蛋白是转铁蛋白超家族的成员，基于几个特征，包括与序列已知的转铁蛋白的32-46%氨基酸位置同一性、内部同源性、半胱氨酸残基的定位和铁结合。而先前表征的昆虫转铁蛋白结合每个蛋白质分子的一个铁原子，B。盘状体转铁蛋白与脊椎动物转铁蛋白一样结合两个铁原子。蟑螂转铁蛋白的二铁特性与存在两组适当定位的残基用于铁结合是一致的。保幼激素抑制转铁蛋白mRNA水平急剧在成年雌性蟑螂。
In a study of juvenile hormone-regulated gene expression, we isolated an anonymous cDNA representing a message that was strongly suppressed by juvenile hormone in the fat body of the cockroach Blaberus discoidalis. The protein deduced from the cDNA sequence showed compelling resemblance in sequence to the transferrins, a superfamily of internally duplicated, 80-kDa iron-binding/transport proteins characterized from several vertebrates and, to date, one insect (the tobacco hornworm, Manduca sexta). We isolated a 78-kDa protein from cockroach hemolymph, verified its congruence with the cloned cDNA, and found that it did bind iron. The cockroach protein is a member of the transferrin superfamily based on several features, including 32-46% amino acid positional identity with transferrins whose sequences are known, internal homology, positioning of cysteine residues, and iron binding. Whereas the previously characterized insect transferrin binds one atom of iron per protein molecule, B. discoidalis transferrin binds two iron atoms as do the vertebrate transferrins. The diferric property of cockroach transferrin is consistent with presence of two sets of residues positioned appropriately for iron binding. Juvenile hormone suppressed transferrin mRNA levels drastically in the adult female cockroach.