Cloning and analysis of cDNAs encoding the hypusine-containing protein eIF5A of two lepidopteran insect species

Eukaryotic initiation factor eIF5A is essential for cell viability and cont ains a characteristic post-translational modification of a specific lysine residue into a hypusine, cDNAs with similarity to eIF5A sequences were deri ved from Spodoptera exigua and S. frugiperda cDNA libraries, The deduced am ino acid sequences are identical for both species and predict a protein wit h a molecular mass of 17.5 kDa. The Drosophila melanogaster eIF5A cDNA sequ ence was retrieved from the Drosophila EST Project. The predicted protein i s 80% similar to Spodoptera eIF5A, A single eIF5A gene copy is present in t he S. frugiperda genome, which is transcribed into four different transcrip ts. Infection of S, frugiperda cells with a baculovirus resulted in a stron g decline of all four transcripts already at 12 h after infection, In contr ast, the eIF5A protein was fairly stable up to 48 h post infection.