Characterization of a gene encoding prohibitin in silkworm, Bombyx mori

BackgroundProhibitin (PHB) is an evolutionarily conserved multifunctional protein with ubiquitous expression. However, its molecular roles are largely unknown.MethodsTo better understand the function of prohibitin protein in silkworm (BmPHB), its coding sequence was isolated from a cDNA library of silkworm pupae. An His-tagged BmPHB fusion protein was expressed in Escherichia coli Rosetta (DE3) and purified with affinity and reversed-phase chromatography. Purified rBmPHB was used to generate anti-BmPHB polyclonal antibody. The subcellular localization of BmPHB was analysed by immunohistochemistry.ResultsBmPHB gene has an ORF of 825 bp, encoding a predicted peptide with 274 amino acid residues. Immunostaining indicate that prohibitin is expressed in nucleus and predominately in cytoplasm. Western blot analyses indicated that, in the fifth instar larva, BmPHB was expressed descendingly in gonad, malpighian tubule, trachea, fatty body, intestine, and head. However, no expression was detected in larva's silk gland and epidermis. In addition, BmPHB was expressed in the nascent egg, larva and pupa, but not in the moth.ConclusionsThe expression of BmPHB gene presents differential characteristic in different stage and tissues. It may play important roles in the development of silkworm.General significanceStudies on prohibitin have been still restricted to a few specific insects and insect cell lines such as Drosophila, Acyrthosiphon pisum and mosquito cell lines, not yet in silkworm. This is a first characterization of prohibitin in silkworm, B. mori.

► We identified a silkworm prohibitin complementary DNA from a pupa cDNA library.
► We investigated the expression of BmPHB in different stage and tissues.
► High expression of BmPHB in gonad and malpighian tubule, low in intestine and head.
► No expression was detected in larva's silk gland and epidermis.
► BmPHB was expressed in the nascent egg, larva and pupa, but not in the moth.