FIGURE 2.

Obst-A is a conserved chitin-binding domain protein with putative homologs among arthropods and nematodes. A, molecular organization of the genomic region 19C1 containing the obst-A gene. Insertions of the obst-A⁶⁶³ P-element and the PiggyBac transposons, used for generation of obst-A^d02 and obst-A^d03 deletion mutants (black lines below indicate the deleted regions), are indicated. Gray bars show the open reading frame, which is similar in both obst-A transcripts. Supporting information, such as Northern blot analysis, is provided in supplemental Fig. S1C. In the deduced Obst-A amino acid sequence (237 aa, MW: 26.5kDa) the N-terminal signaling peptide is indicated in green and the three type 2 chitin-binding-domains in red. The underlined sequence at the C terminus shows the peptide used to generate the anti-Obst-A antibody. B, diagram shows the signaling peptide (SP, green), chitin-binding domains (CBD2, red) and a C-terminal stretch of Obst-A. Domains were annotated with the SMART database and the SignalP 4.0 Server. C, phylogenetic analysis of Obst-A sequence identified homologs in different nematodes and arthropods (accession numbers see supplement; MEGA 5.0 alignment).