稻纵卷叶螟ABCG3转运蛋白的分子特性与基因表达谱分析

Molecular characteristics and gene expression of the Cnaphalocrocis medinalis(Guenée)ABCG3 transporter protein

【目的】三磷酸腺苷结合盒转运子(ATP-binding cassette transporters,ABC转运蛋白)是广泛存在于各生物体内的一类跨膜蛋白,参与生物体内营养物质及外源毒物的转运。明确稻纵卷叶螟Cnaphalocrocis medinalis ABCG3的分子特性与表达谱特征,是开展该基因功能研究的基础。【方法】利用生物信息学方法分析稻纵卷叶螟ABCG3转运蛋白的分子特性,利用定量PCR技术分析了其时空表达谱。【结果】稻纵卷叶螟ABCG3含有一个跨膜结构域(TMD)和核酸结合结构域(NBD),属于半转运蛋白,包含1055个氨基酸,分子量和等电点分别为118.95ku和8.78,表达位置位于内质网。稻纵卷叶螟ABCG3蛋白包含43.51%的α-螺旋、7.01%的β-转角、18.29%的片层和31.18%的无规则卷。通过建立稻纵卷叶螟ABCG3与其他5种鳞翅目昆虫的ABCG亚家族系统发育进化树,发现稻纵卷叶螟ABCG3与黑脉金斑蝶Danaus plexippu亲缘关系最为接近。稻纵卷叶螟ABCG3基因在各龄期中及在前肠、中肠、后肠、血淋巴和脂肪体中均有表达,其中在5龄幼虫中的表达量高于其他龄期,血淋巴和脂肪体中的表达量较高。【结论】本研究明确了稻纵卷叶螟ABCG3蛋白的结构特征及时空表达特征。这对于阐明稻纵卷叶螟ABC转运蛋白家族的结构特征和表达模式具有重要意义,为今后稻纵卷叶螟ABC转运蛋白的功能研究奠定基础。

[Objectives]To improve understanding of the characteristics and expression profile of the Cnaphalocrocis medinalis ABCG3 protein,one of the ATP-binding cassette transporter(ABC transporter)transmembrane proteins found in many organisms that is involved in the transport of nutrients and exogenous toxins.[Methods]We used bioinformatics to investigate the molecular properties of the C.medinalis ABCG3 transporter protein,and RT-qPCR to determine its expression patterns in different larval instars and tissues.[Results]C.medinalis ABCG3 is a half-transporter protein with 1055 amino acids,a molecular weight of 118.95 ku and an isoelectric point of 8.78.It has a transmembrane domain(TMD)and a nucleic acid binding domain(NBD).The protein is predicted to be located in the endoplasmic reticulum,and has a 43.51%α-helix,a 7.01%β-angle,a 18.29%lamellae and a 31.18%irregular roll.A phylogenetic tree of C.medinalis ABCG3 and that of five other lepidopteran species suggests that C.medinalis ABCG3 is most closely related to that of the monarch butterfly(Danaus plexippus).The ABCG3 gene was found to be expressed in all larval instars and tissues that were investigated.Expression was higher in fifth instar larvae than in other instars,and higher in the hemolymph and fat body than in other tissues.[Conclusion]These findings clarify the structural properties and expression patterns of the ABC transporter family in C.medinalis,and thereby provide a platform for further investigation of the function of ABC transporters in this species.