Rananos expression pattern during oogenesis and early embryonic development in Rhynchosciara americana.

The Dipteran Rhynchosciara americana, a native Brazilian insect that has become a valuable model system for developmental biology research because it provides an interesting opportunity to study a different type of insect oogenesis. Sequences from a cDNA library that was constructed with poly A+RNA from the ovaries of R. americana larvae at different ages were analyzed. Molecular characterization confirmed interesting findings, such as the presence of Rananos. The nanos gene encodes a conserved RNA-binding protein that is required during early development for the maintenance and division of the primordial germ cells of Diptera. nanos plays an important role in specifying the posterior regions of insect embryos and is important for abdomen formation. In the present work, we showed the spatial and temporal expression profiles of this important gene, which is involved in oogenesis and early development. Data mining techniques were used to obtain the complete sequence of Rananos. Bioinformatic tools were used to determine the following: (1) the secondary structure of the 3'-untranslated region of the Rananos mRNA, (2) the encoded protein of the isolated Rananos gene, (3) the conserved zinc-finger domains of the RaNanos protein, and (4) phylogenetic analyses. Furthermore, RNA in situ hybridization and immunolocalization were used to determine mRNA and protein expression in the tissues that were studied and to define Rananos as a germ cell molecular marker.