Molecular-Phylogenetic Characterization of Arrestin-2 from Maruca vitrata (Lepidoptera: Crambidae)

Most physiological processes to external stimulants rely upon intracellular signal transduction mediated by ligand binding of G-protein-coupled receptors. The G-protein signaling pathway is deactivated by arrestin-2 binding, which is indispensable for receptor internalization and recycling. We identified the full-length cDNA encoding arrestin-2 in Maruca vitrata F. using rapid amplification of cDNA ends. The open reading frame of MaviArr2 is 1,221 bp in length, encoding 407 amino acids. The alignment of the known arrestin-2 amino acid sequences from other insects revealed that MaviArr2 has the highest similarity (98.8%) to the monarch butterfly, but shows low homology (53.9–60.7%) with ants and bees. A certain number of highly conserved protein-binding motifs were identified from the deduced MaviArr2 amino acids, demonstrating their function as receptor deactivators in signal transduction pathways in cells. The genomic DNA sequence of MaviArr2, amplified by polymerase chain reaction, is 1,779 bp in size and is composed of six exons. Real-time quantitative polymerase chain reaction assay demonstrated a relatively higher expression of MaviArr2 mRNA in the late pupal stages, suggesting multiple developmental functions. Phylogenetic analysis showed the lepidopteran arrestin-2 protein sequence is closely related to that of Diptera, but distant from Hymenoptera arrestin-2. Intraspecific genomic sequence comparisons of MaviArr2 show a greater conservation of the gene in M.vitrata from Africa than those from geographical locations in Asia. These findings are a significant step forward in our understanding of arrestin-2 gene architecture and functions, which may provide a possibility to manage M.vitrata through molecular and phylogenetic techniques.