RNAi reveals the key role of Nervana 1 in cockroach oogenesis and embryo development

Na+, K+-ATPases is a heterodimer protein consisting of α- and β-subunits that control the ion transport through cell membranes. In insects the β-subunit of the Na+, K+-ATPase, known as Nervana, was characterized as a nervous system-specific glycoprotein antigen from adult Drosophila melanogaster heads. Nervana is expressed ubiquitously in all insect tissues, and in epithelial cells appeared located in a basolateral position as part of the septate junctions. Herein we study two Nervana isoforms from Blattella germanica, a cockroach species with panoistic ovaries. The sequencing and the phylogenetic analysis results suggest that these two isoforms are orthologs of D. melanogaster Nervana 1 and Nervana 2, respectively. Nervana 1 is highly expressed in the ovary of B. germanica, and depleting its expression results in changes in oocyte shape that do not impair oviposition. However, the resulting embryos show different defects and never hatch. These findings highlight the importance of this type of membrane pump in insect oogenesis as well as in embryo development, and its possible regulation by juvenile hormone. © 2012 Elsevier Ltd.This work was supported by the Ministry of Science and Innovation, Spain (projects BFU2008-00484 and BFU2011-22404 to MDP), and by the CSIC (grant 2010TW0019, Formosa program). PI is recipient of a postdoctoral research grant (BECAS CHILE) from the “Comisión Nacional de Investigación Científica y Tecnológica” (CONICYT, Chile). FAST was supported by a fellowship from FAPESP, to do a stage in the IBE.Peer Reviewe