Characterization and recombinant protein expression of ferritin light chain homologue in the silkworm, Bombyx mori. (12th September 2013)

• Record Type: Journal Article
• Authors: Hong, Sun Mee; Mon, Hiroaki; Lee, Jae Man; Kusakabe, Takahiro
• Is Part Of: Insect science. Volume 21:Number 2(2014:Apr.)
• Page Start: 135
• Page End: 146
• Publication Date: 2013-09-12
• Subjects: Insects -- Periodicals; Entomology -- Periodicals; 595.705
• DOI: 10.1111/1744-7917.12031
• Languages: English
• ISSNs: 1672-9609

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The silkworm genome encodes three iron storage proteins or ferritins, <italic>Fer1HCH</italic>, <italic>Fer2LCH</italic>, and <italic>Fer3HCH</italic>. Probing our EST library constructed from 1‐day‐old silkworm eggs revealed only <italic>Fer2LCH</italic> mRNA, which encoded for a protein with a predicted putative <italic>N</italic>‐glycosylation site. Developmental and tissue expression analyses during embryogenesis revealed that <italic>Fer2LCH</italic> mRNA was abundant from 6 h to 6 days after oviposition. Transcriptional expression of <italic>Fer2LCH</italic> 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 <italic>Fer2LCH</italic> 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 <italic>Fer2LCH</italic> mRNA were not significantly induced following viral or bacterial infection of <italic>Bombyx mori</italic>. 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 <italic>N</italic>‐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.</p> </abstract>