Exploratory Survey of Transposable Element-Associated Proteins in the Terrestrial Isopod Armadillidium vulgare

Transposable elements (TEs) are major contributors to genome evolution, structural diversification, and genome expansion in eukaryotes. Although the terrestrial isopod Armadillidium vulgare possesses a relatively large genome among arthropods, TE-associated protein sequences in this species remain poorly characterized. In this study, we performed an exploratory survey of TE-associated proteins in A. vulgare using publicly available genome-derived protein datasets. Known TE-related proteins, including piggyBac transposase, Mariner/Mos1 transposase, and Gypsy retrotransposon polyprotein sequences, were used as BLASTp queries against the predicted protein dataset of A. vulgare. An initial permissive BLASTp search identified 271 hits, and subsequent filtering based on sequence identity (≥30%) and query coverage (≥50%) yielded 27 candidate TE-associated proteins. Conserved domain analyses detected DDE transposase-related domains in multiple candidates, including DDE_Tnp_1_7 and Transposase_1 domains. Several Gypsy-like candidates exhibited conserved combinations of RT_LTR, RNase_HI_RT_Ty3, and Integrase_H2C2 domains, consistent with canonical LTR retrotransposon polyprotein organization. Phylogenetic analysis of piggyBac-like candidates further supported their clustering with known piggyBac transposase sequences. These findings provide an initial catalog of putative TE-associated proteins in A. vulgare and suggest the presence of diverse transposase-related sequences in the genome of this terrestrial isopod.