title: Molecular cloning and copy number variation of a ferritin subunit (Fth1) and its association with growth in freshwater pearl mussel Hyriopsis cumingii.
abstract: Iron is one of the most important minor elements in the shells of bivalves. This study was designed to investigate the involvement of ferritin, the principal protein for iron storage, in shell growth. A novel ferritin subunit (Fth1) cDNA from the freshwater pearl mussel (Hyriopsis cumingii) was isolated and characterized. The complete cDNA contained 822 bp, with an open reading frame (ORF) of 525 bp, a 153 bp 5' untranslated region (UTR) and a 144 bp 3' UTR. The complete genomic DNA was 4125 bp, containing four exons and three introns. The ORF encoded a protein of 174 amino acids without a signal sequence. The deduced ferritin contained a highly conserved motif for the ferroxidase center comprising seven residues of a typical vertebrate heavy-chain ferritin. It contained one conserved iron associated residue (Try27) and iron-binding region signature 1 residues. The mRNA contained a 27 bp iron-responsive element with a typical stem-loop structure in the 5'-UTR position. Copy number variants (CNVs) of Fth1 in two populations (PY and JH) were detected using quantitative real-time PCR. Associations between CNVs and growth were also analyzed. The results showed that the copy number of the ferritin gene of in the diploid genome ranged from two to 12 in PY, and from two to six in JH. The copy number variation in PY was higher than that in JH. In terms of shell length, mussels with four copies of the ferritin gene grew faster than those with three copies (P<0.05), suggesting that CNVs in the ferritin gene are associated with growth in shell length and might be a useful molecular marker in selective breeding of H. cumingii.
authors.affiliation: Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai Ocean University, Shanghai, China.
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Bai
authors.forename: Yiming
authors.initials: Y
authors.lastname: Yuan
authors.forename: Genhua
authors.initials: G
authors.lastname: Yue
authors.forename: Jiale
authors.initials: J
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001052:Apoferritins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D049872:Bivalvia / Q000235:genetics* / Q000254:growth & development*; D003001:Cloning, Molecular; D056915:DNA Copy Number Variations / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D005618:Fresh Water; D016678:Genome / Q000235:genetics; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics*; D020218:Response Elements / Q000235:genetics; D016415:Sequence Alignment; D013045:Species Specificity; D040681:Structural Homology, Protein
chemical_list: D018076:DNA, Complementary; D021122:Protein Subunits; D001052:Apoferritins