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.

Sequencing, De Novo Assembly, and Annotation of the Transcriptome of the Endangered Freshwater Pearl Bivalve, Cristaria plicata, Provides Novel Insights into Functional Genes and Marker Discovery

“…A summary of the top-hit InterPro domains identified 1,374 unigenes with zinc finger, C2H2-like domains. Zinc finger domains participate in important cell processing functions including signal transduction and transcriptional regulation and are a common feature in molluscs, insects, and other crustacean groups [ 60 , 61 ]. The C2H2-like zinc finger proteins are the most common DNA-binding motifs present in prokaryotic and eukaryotic transcription factors [ 62 ].…”

First insights into the giant panda (Ailuropoda melanoleuca) blood transcriptome: a resource for novel gene loci and immunogenetics

“…; Bai et al . ). We also examined the expression level of MHC genes and found that Aime‐128 MHC class I gene is expressed far greater than other MHC genes (Pan et al .…”

Extensive genome-wide duplications in the eastern oyster (Crassostrea virginica)

“…Because the growth of the aquaculture industry is threatened by disease and environmental change, it is important to consider how genomic variation can be exploited for breeding purposes, particularly disease resistance [74,75]. The variation observed here in C. virginica can serve as an important resource for the discovery of candidate genes and markers for developing lines with important traits crucial for aquaculture, such as disease resistance or increased growth [24,98,99]. On the other hand, the limited duplications seen in inbred individuals compared with those in the wild suggests that caution may be necessary to avoid losing genetic diversity in commercial breeding programs while selecting for relevant traits [100].…”