PMC

Schematic representation of the four cloned APN cDNAs. Gray bars correspond to the respective ORF. White blocks inside the gray bars represent the cDNA fragments coming from the SSH experiments and numbers correspond to the contig name. The black lines over each bar correspond to the fragment of RNA probe used in the Northern blots.

ClustalX aligment of the deduced amino acid sequences from the four Spodoptera exigua aminopeptidases. Dashed lines enclose the predicted signal peptides. Solid lines box the putative Zinc binding motives. The GAMEN motif is underlined. Predicted GPI-modification sites in the C-terminal sequence are indicated by the black triangles.

Northern blot analysis of APN expression in 5^th instar midguts and whole neonate larvae of Spodoptera exigua. A. Comparison of expression of APNs in midguts from control (-) and toxin-exposed larvae (1Ca). An ATP synthase transcript (ATPsyn) was used as an internal control of RNA extraction and gel loading. B. Expression of APNs in midguts from fifth instar larvae (left panel) and whole neonate larvae (right panel) of the susceptible (S) and of the Cry1Ca-resistant (R) line. Higher molecular weight bands correspond to the different APN transcripts. Lower molecular weight bands correspond to the ATPsynthase transcripts.

Phylogenetic tree derived from a ClustalX alignment of all published lepidopteran midgut aminopeptidases. Species name and GenBank accession number are shown for each protein. Numbers on the branches report the level of confidence as determined by bootstrap analysis (1000 bootstrap replicates). To clarify the figure, bootstrap values are shown only for the main branches. The scale bar indicates an evolutionary distance of 0.1 amino acid substitutions per position in the sequence. Species abbreviations: Se: Spodoptera exigua; Ms: Manduca sexta; Ld: Lymantria dispar; Hv: Heliothis virescens; Ha: Helicoverpa armigera; Hp: Helicoverpa punctigera; Bm: Bombyx mori; Sl: Spodoptera litura; Px: Plutella xylostella; Pi: Plodia interpunctella; Ep: Epiphyas postvittana