Hu Xiaobang, Leming Matthew T, Whaley Michelle A, O'Tousa Joseph E
Department of Biological Sciences and the ECK Institute for Global Health, Galvin Life Science Building, University of Notre Dame, Notre Dame, IN 46556, USA.
J Exp Biol. 2014 Mar 15;217(Pt 6):1003-8. doi: 10.1242/jeb.096347. Epub 2013 Dec 5.
Differential rhodopsin gene expression within specialized R7 photoreceptor cells divides the retinas of Aedes aegypti and Anopheles gambiae mosquitoes into distinct domains. The two species express the rhodopsin orthologs Aaop8 and Agop8, respectively, in a large subset of these R7 photoreceptors that function as ultraviolet receptors. We show here that a divergent subfamily of mosquito rhodopsins, Aaop10 and Agop10, is coexpressed in these R7 photoreceptors. The properties of the A. aegypti Aaop8 and Aaop10 rhodopsins were analyzed by creating transgenic Drosophila expressing these rhodopsins. Electroretinogram recordings, and spectral analysis of head extracts, obtained from the Aaop8 strain confirmed that Aaop8 is an ultraviolet-sensitive rhodopsin. Aaop10 was poorly expressed and capable of eliciting only small and slow light responses in Drosophila photoreceptors, and electroretinogram analysis suggested that it is a long-wavelength rhodopsin with a maximal sensitivity near 500 nm. Thus, coexpression of Aaop10 rhodopsin with Aaop8 rhodopsin has the potential to modify the spectral properties of mosquito ultraviolet receptors. Retention of Op10 rhodopsin family members in the genomes of Drosophila species suggests that this rhodopsin family may play a conserved role in insect vision.
在埃及伊蚊和冈比亚按蚊的视网膜中，专门的R7光感受器细胞内视紫红质基因的差异表达将视网膜划分为不同的区域。这两个物种分别在这些作为紫外线感受器的R7光感受器的很大一部分中表达视紫红质直系同源物Aaop8和Agop8。我们在此表明，蚊子视紫红质的一个不同亚家族Aaop10和Agop10在这些R7光感受器中共表达。通过创建表达这些视紫红质的转基因果蝇，分析了埃及伊蚊Aaop8和Aaop10视紫红质的特性。从Aaop8菌株获得的视网膜电图记录和头部提取物的光谱分析证实Aaop8是一种对紫外线敏感的视紫红质。Aaop10表达不佳，在果蝇光感受器中仅能引发微小且缓慢的光反应，视网膜电图分析表明它是一种最大灵敏度接近500nm的长波长视紫红质。因此，Aaop10视紫红质与Aaop8视紫红质的共表达有可能改变蚊子紫外线感受器的光谱特性。果蝇物种基因组中Op10视紫红质家族成员的保留表明，这个视紫红质家族可能在昆虫视觉中发挥保守作用。
