Molecular Analysis of the Alpha-Tubulin Gene from the Microsporidium, Endoreticulatus sp. Zhenjiang, Isolated from Bombyx mori

We isolated a microsporidium from the silkworm, Bombyx mori, and classified it as Endoreticulatus sp. Zhenjiang based on morphological characteristics and phylogenetic analyses of ribosomal sequences. This microsporidium causes silkworm pebrine, although its original host and mode of transmission are unknown. To better understand its distribution and transmission mode, it is essential to have species specific molecular markers. Towards this goal, we characterized the alpha tubulin gene from Endoreticulatus sp. Zhenjiang in this study. The full-length alpha-tubulin cDNA from Endoreticulatus sp. Zhenjiang was cloned and sequenced (GenBank ID: KJ784483) using the rapid amplification of cDNA ends (RACE) protocol. The alpha-tubulin cDNA is 1382 bp long with an open reading frame spanning 1320 bp and consisting of a short 20-bp 5’-untranslated region (5’-UTR) and a 42-bp 3’-UTR with a stop codon and a poly (A) tail. This alpha-tubulin cDNA encodes a deduced polypeptide with 439 amino acids, including a complete tubulin domain and a tubulin C domain. This protein has an estimated isoelectric point of 5.1 and a predicted molecular weight of 48.6 kDa.