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Characterization and recombinant protein expression of ferritin light chain homologue in the silkworm, Bombyx mori
Author(s) -
Hong Sun Mee,
Mon Hiroaki,
Lee Jae Man,
Kusakabe Takahiro
Publication year - 2014
Publication title -
insect science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 45
eISSN - 1744-7917
pISSN - 1672-9609
DOI - 10.1111/1744-7917.12031
Subject(s) - biology , bombyx mori , glycosylation , ferritin , messenger rna , bombyx , recombinant dna , protein subunit , gene expression , microbiology and biotechnology , gene , biochemistry
The silkworm genome encodes three iron storage proteins or ferritins, Fer1HCH , Fer2LCH , and Fer3HCH . Probing our EST library constructed from 1‐day‐old silkworm eggs revealed only Fer2LCH mRNA, which encoded for a protein with a predicted putative N ‐glycosylation site. Developmental and tissue expression analyses during embryogenesis revealed that Fer2LCH mRNA was abundant from 6 h to 6 days after oviposition. Transcriptional expression of Fer2LCH during the postembryonic stage is also high in the larval fat body and mid‐gut, and then is upregulated in all pupal tissues tested. We found that Fer2LCH mRNA contains an iron‐responsive element, suggesting this ferritin subunit is subject to translational control. Although ferritin expression has been shown to increase following immune challenge in other insects, the levels of Fer2LCH mRNA were not significantly induced following viral or bacterial infection of Bombyx mori . Using a baculovirus expression system we expressed recombinant BmFer2LCH protein, which was detectable in the cytoplasmic fraction, likely in a compartment of the secretory pathway, and was shown to undergo posttranslational modifications including N ‐glycosylation. In particular, rBmFer2LCH carbohydrate chains were composed of mannose and GlcNAc. We suggest that Fer2LCH is important for iron homeostasis and maintaining normal organ function in silkworms.