Figure 1

Structure of the Drosophila synapsin gene and genomic and cDNA sequences near the protein kinase target motif, including the encoded amino acids. The base modified by RNA editing is boxed. (A). Schematic representation of the synapsin locus of Drosophila melanogaster showing the exon-intron structure of the gene. Underneath, a close-up view of exons 4 and 5 with the sequence from the Berkeley Drosophila Genome Project and five different wild-type strains at this site is depicted. The encoded amino acids are indicated under each codon by the one letter code, bold letters mark the kinase target motif RRFS. (B). cDNA sequences from an earlier publication [26] and five different wild-type lines. The region surrounding the phosphorylation target motif in the synapsin cDNA was amplified by nested RT-PCR and sequenced. The relevant codons and the corresponding amino acids are shown. The genomic kinase target motif RRFS is modified to RGFS at the cDNA level (bold letters). In two wild-type strains partial editing also modifies the first arginine of the motif. (C). Amino acid sequence obtained by Edman degradation of purified Drosophila synapsin. At most positions two amino acids were detected, resulting from an unknown contamination (from [27]). The sequence is compatible only with the cDNA encoded version of the kinase target motif (bold letters).