In living organisms,ferritin plays an important role in iron storage and detoxification.The full-length cDNA sequence of a ferritin(EsFer)was obtained from the cDNA library of the Chinese mitten crab Eriocheir sinensis stimulated with lipopolysaccharide(LPS).It has 1 118 bp in length and contains a 480 bp open reading frame(ORF)encoding 159 amino acids(aa).The 5′and 3′untranslated region(UTR)is 178 bp and 461 bp,respectively.The predicted molecular weight is 18.3 ku and the theoretical isoelectric point 5.81.A transmembrane helix was found at the position of 15-37 aa.A complete ironresponsive element(IRE)was found at the 5′ untranslated region corresponding to the nucleotide sequence at the positions of the 135-162.Quantitative realtime PCR was used to assess the mRNA expression of EsFer in organs or tissues and its induced expression in haemolymph,intestine,hepatopancreas of crabs challenged with LPS.The results showed that EsFer was expressed in all tested organs or tissues of the Chinese mitten crab,including haemolymph,muscle,intestine,gills,heart,gonad and hepatopancreas.The highest expression level was observed in hepatopancreas,while the lowest in haemolymph.The expression of EsFer in haemolymph,intestine and hepatopancreas was upregulated following the challenge with LPS.