Figure 1. Schematic diagram of the genomic organization of Gyc-89Da and Gyc-89Db and the other soluble guanylyl cyclase subunit genes in Drosophila melanogaster. The upper line shows the relative positions of all 5 genes on the right arm of the third chromosome. The region containing Gyc-89Da and Gyc-89Db is expanded showing their proximity to each other (separated by about 2 kb) and their similar intron/exon structure. The coding region of both genes is contained in a single exon (grey box) that is preceded by a intron and a non-coding 5' exon (open box). There are two splice variants of Gyc-89Da that differ in the splice site between the first exon and first intron – one variant containing an additional 14 bp in the first exon. The first exon/intron boundary for each splice variant is shown with upper case letters representing the sequence of the exon. The 3' UTR of Gyc-89Da was not determined but gene prediction software predicted the poly-A signal 84 bp 3' of the stop codon (not shown). The 5' and 3'UTRs of Gyc-89Db were included in the expressed sequence tag obtained from the Berkeley Drosophila Genome Project.