Abstract:
Ferritins are iron binding proteins made out of 24 subunits, involved in iron homeostasis and metabolism
in cellular environments. Here, we sought to identify and functionally characterize a one type of subunits
of ferritin (ferritin H-like subunit) from rock bream (Oplegnathus fasciatus; RbFerH). The complete coding
sequence of RbFerH was 531 bp in length, encoding a 177-amino acid protein with a predicted molecular
mass of 20.8 kDa. The deduced protein structure possessed the domain architecture characteristic of
known ferritin H subunits, including metal ligands for iron binding, a ferroxidase center, and two
iron-binding region signatures. As expected, the 50 untranslated region of the RbFerH cDNA sequence
contained a putative iron response element region, a characteristic regulatory element involved in its
translation. The RbFerH gene comprised 5 exons and 4 introns spanning a 4195 bp region. Overexpressed
recombinant RbFerH protein demonstrated prominent Fe(II) ion depriving activity, bacteriostatic properties, and protective effects against oxidative double-stranded DNA damage. Using quantitative polymerase chain reaction (qPCR), we found that RbFerH was expressed ubiquitously in the majority of
physiologically important tissues in rock bream. A greater abundance of the mRNA transcripts were
detected in blood and liver tissues. Upon administering different microbial pathogens and pathogenderived mitogens, RbFerH transcription was markedly elevated in the blood of rock bream. Taken
together, our findings suggest that RbFerH acts as a potent iron sequestrator in rock bream and may
actively participate in antimicrobial as well as antioxidative defense.
