Correspondance between exons and protein regions in the elav family of D. melanogaster. A: RNA structures. RNA nomenclature as in FlyBase, with details in the Methods. Boxes represent exons. The black horizontal lines are introns, with dashes respectively replacing the 5.8 kb long intron in the rbp9-RA transcript and the 2.2 kb long intron in the elav-RA transcript. White: non coding, Vertical stripes: non-conserved, Crossed: gene-specific mini-exons, respectively a 15 nucleotide long region present in alternative forms of rbp9 and a 45 nucleotide long region present in fne. All others are color coded based upon sequence similarity and according to exon-exon boundaries. B: Schematic representation of the ELAV family protein products. The color coding corresponds to that used for the RNA representation. The regions encoded by gene specific sequences have been omitted. RRM: RNA Recogntion Motif. The pairs of white vertical bars represent conserved motifs (RNP-1 and RNP-2) diagnostic of RRMs.