Abstract:

COMMDs are recently discovered in many multicellular organisms. They are involved in numerous aspects of biological processes, such as the regulation of copper homeostasis, the transport of sodium ions, the activity of the transcription factors NF-κB, and hypoxia-inducible factor (HIF-1). To investigate the role of Commd1 in response to salt stress, we first cloned Commd1 cDNA using Rapid Amplification of the cDNA Ends (RACE) technique in mollusks, Crassostrea hongkongensis (designed ChCommd1). The full-length cDNA is 841 bp containing a 5′-untranslated region (UTR) in 18 bp, a 3′-UTR in 262 bp with a poly (A) tail, and an open reading frame (ORF) in 564 bp; the ORF encodes a 187 amino-acid polypeptide with a predicted molecular mass of 21.79 kDa and an isoelectric point of 5.21. Homologous comparison and phylogenetic analysis revealed that the 187-aa-long ChCOMMD1 protein shares high sequence identity with its homologs from other species and belongs to the molluscan COMMD1 family. Quantitative real-time PCR analysis showed that ChCommd1 mRNA is broadly expressed in various tissues and during different stages of the oyster’s embryonic and larval development. Upon exposure to two stressors (high and low salinity), the expression level of ChCommd1 mRNA increased significantly. Taken together, our results indicated that ChCommd1 can function in the embryonic development and osmotic regulation, providing an important reference for further investigations on the functions of Commd1 in the euryhaline mollusks.

Key words: C. hongkongensis, Commd1, gene expression, salinity stress