Mytilus galloprovincialis ferritin: gene and cDNA sequence analysis

Ferritin plays a central role in the maintenance of intracellular balance of iron required for normal cell growth and proliferation. The function of ferritins is to store and release ferrous iron (Fe2+). During iron uptake, ferritin tends to lower Fe2+ concentration, thus competing with Fenton reactions and limiting formation of toxic reactive oxygen species (ROS) and vice versa. The metal chelator, ferritin molecule is a protein shell composed of 24 protein chains arranged in 2, 3, 4 point symmetry, with the capacity to sequester up to 4500 atoms of iron in a ferrihydrite mineral core. In this study we characterize full length M. galloprovincialis ferritin cDNA. The ferritin cDNA transcript with the 5’ and 3’ untranslated regions is 791 bp long. The putative open reading frame (114-638 bp) encodes a polypeptide of 174 amino acids, with a theoretical pI/Mw 4.88/ 20.114 kDa and three conserved domains: ferroxidase diiron center, ferrihydrite nucleation center and iron ion channel. According to the bioinformatics analysis, this ferritin is likely to be a homolog of vertebrate H-ferritin. The ferritin expression is regulated at both transcriptional and translational levels. The iron levels in the cell regulate the ferritin translation, removing the interaction between iron regulatory protein (IRP) and iron response element (IRE ; 17-44 bp). In response to oxidative stress, the cells activate a defence strategy using ferritin to restrict the metal availability, so the ferritin as an anti/pro-oxidant agent in musell M. galloprovincialis has a potential application as biomarker of oxidative stress and environmental pollution