Yates R A, Tuan R S, Shepley K J, Unnasch T R
Division of Geographic Medicine, University of Alabama at Birmingham 35294, USA.
Mol Biochem Parasitol. 1995 Mar;70(1-2):19-31. doi: 10.1016/0166-6851(95)00018-v.
Several lines of evidence suggest that molting in parasitic nematodes is controlled through the action of steroid molting hormones, or ecdysones. In other organisms, the central mediator of steroid hormone action is the hormone receptor. These receptor molecules are members of a superfamily of proteins called the nuclear hormone receptor family. Using an oligonucleotide derived from the amino-acid sequence of the Drosophila melanogaster ecdysone receptor, genes encoding homologues of the nuclear hormone receptor family were identified in the genome of the human filarial parasite Onchocerca volvulus. The O. volvulus genome contains at least three genes that encode putative members of the nuclear hormone receptor superfamily. A complete cDNA for one of these genes, designated OvNHR-1, has been isolated and characterized. The OvNHR-1 cDNA was 2378 bp in length, and contained a single open reading frame of 1104 bp. The open reading frame encoded a peptide with all of the features characteristic of a member of the nuclear hormone receptor superfamily of proteins. OVNHR-1 appeared to be encoded by a single-copy gene. Expression of the mRNA corresponding to OvNHR-1 was developmentally regulated, with maximal expression occurring during early embryogenesis. The polypeptide encoded by the OvNHR-1 open reading frame is antigenic in a minority of individuals exposed to O. volvulus.
多项证据表明，寄生线虫的蜕皮过程是由类固醇蜕皮激素（即蜕皮酮）的作用所控制的。在其他生物中，类固醇激素作用的核心介质是激素受体。这些受体分子是一个名为核激素受体家族的蛋白质超家族的成员。利用从黑腹果蝇蜕皮激素受体的氨基酸序列推导而来的寡核苷酸，在人类丝虫寄生虫旋盘尾丝虫的基因组中鉴定出了编码核激素受体家族同源物的基因。旋盘尾丝虫基因组至少包含三个编码核激素受体超家族推定成员的基因。其中一个基因（命名为OvNHR - 1）的完整cDNA已被分离并鉴定。OvNHR - 1 cDNA长度为2378 bp，包含一个1104 bp的单一开放阅读框。该开放阅读框编码一种具有核激素受体蛋白质超家族成员所有特征的肽。OvNHR - 1似乎由单拷贝基因编码。与OvNHR - 1相对应的mRNA的表达受到发育调控，在胚胎发育早期表达量最高。由OvNHR - 1开放阅读框编码的多肽在少数接触旋盘尾丝虫的个体中具有抗原性。
