Dimerization of oskar 3' UTRs promotes hitchhiking for RNA localization in the Drosophila oocyte.

mRNA localization coupled with translational control is a highly conserved and widespread mechanism for restricting protein expression to specific sites within eukaryotic cells. In Drosophila, patterning of the embryo requires oskar mRNA transport to the posterior pole of the oocyte and translational repression prior to localization. oskar RNA splicing and the 3' untranslated region (UTR) are required for posterior enrichment of the mRNA.

Anopheles gambiae miRNAs as actors of defence reaction against Plasmodium invasion.

The path Plasmodium takes across the Anopheles midgut constitutes the major bottleneck during the malaria transmission cycle. In the present study, using a combination of shot-gun cloning and bioinformatic analysis, we have identified 18 miRNAs from Anopheles gambiae including three miRNAs unique to mosquito. Twelve of them are expressed ubiquitously across the body, independently of gender, while the other six exhibited an expression pattern restricted to the digestive system.

Secondary structure of the 3' UTR of bicoid mRNA.

Formation of the Bicoid morphogen gradient in early Drosophila embryos requires the pre-localization of bicoid mRNA to the anterior pole of the egg. The program of bcd mRNA localization involves multiples steps and proceeds from oogenesis until early embryogenesis. This process requires cis-elements in the 3' UTR of bcd mRNA and successive and/or concomitant critical protein interactions.

Mechanism of dimerization of bicoid mRNA: initiation and stabilization.

Dimerization of bcd mRNA was shown to be important for the formation of ribonucleoprotein particles and their localization in Drosophila embryo. The cis-element responsible for dimerization is localized in a stem-loop domain (domain III) containing two essential complementary 6-nucleotide sequences in a hairpin loop (LIIIb) and an interior loop (LIIIa). Such an RNA element can potentially generate single or double "hand-by-arm" interactions leading to open and closed complexes, respectively.

RNA loop-loop interactions as dynamic functional motifs.

RNA loop-loop interactions are frequently used to trigger initial recognition between two RNA molecules. In this review, we present selected well-documented cases that illustrate the diversity of biological processes using RNA loop-loop recognition properties. The first one is related to natural antisense RNAs that play a variety of regulatory functions in bacteria and their extra-chromosomal elements.