Characterization and functional analysis of a chitin synthase gene (HcCS1) identified from the freshwater pearlmussel Hyriopsis cumingii

Abstract

ABSTRACT. The triangle sail mussel, Hyriopsis cumingii, is the most important freshwater pearl mussel in China. However, the mechanisms underlying its chitin-mediated shell and nacre formation remain largely unknown. Here, we characterized a chitin synthase (CS) gene (HcCS1) in H. cumingii, and analyzed its possible physiological function. The complete ORF sequence of HcCS1 contained 6903 bp, encoding a 2300-amino acid protein (theoretical molecular mass = 264 kDa; isoelectric point = 6.22), and no putative signal peptide was predicted. A myosin motor head domain, a CS domain, and 12 transmembrane domains were found. The predicted spatial structures of the myosin head and CS domains were similar to the electron microscopic structure of the heavy meromyosin subfragment 19264-19274 (2015) of chicken smooth muscle myosin and the crystal structure of bacterial cellulose synthase, respectively. This structural similarity indicates that the functions of these two domains might be conserved. Quantitative reverse transcription PCR results showed that HcCS1 was present in all detected tissues, with the highest expression levels detected in the mantle. The HcCS1 transcripts in the mantle were upregulated following shell damage from 12 to 24 h post-damage, and they peaked (approximately 1.5-fold increase) at 12 h after shell damage. These findings suggest that HcCS1 was involved in shell regeneration, and that it might participate in shell and nacre formation in this species via chitin synthesis. HcCS1 might also dynamically regulate chitin deposition during the process of shell and nacre formation with the help of its conserved myosin head domain.

Prior Toxoplasma Gondii Infection Ameliorates Liver Fibrosis Induced by Schistosoma Japonicum through Inhibiting Th2 Response and Improving Balance of Intestinal Flora in Mice

“…ChamQTM SYBR ® qPCR Master Mix (Vazyme, Nanjing, China) was used in real-time quantitative PCR. The average cycle thresholds (Ct) were calculated by using 2-∆∆CT method which was used to calculate relative gene expression levels [55]. The primers for HSP47: 5 -ACC GAG CCC TCT TCA GTC TT-3 (Forward), 5 -GGT GAT GCC CAA CAT AAC AAT-3 (Reverse).…”

β‐Chitin and chitosan from waste shells of edible mollusks as a functional ingredient

“…CHS gene from freshwater pearl mussel H. cumingii was sequenced using a molecular cloning technique, revealing the presence of myosin head domain (Zheng et al, 2015). Myosin motor head domain function was predicted to be inhibiting the mineralization process and thereby regulating the chitin deposition.…”

“…Phylogenetic analysis revealed that CHS genes of most crustacean species were clustered together and more specific to arthropods closely related to insects (Zhang et al., 2021). This made them distant from mollusk CHS (Zheng et al., 2015). Further phylogenetic analysis revealed that the CHS gene of mollusk Hyriopsis cumingii , Pinctada fucata , Atrina rigida , and Mytilus galloprovincialis were similar in identity.…”

“…The theoretical molecular mass of mollusk was higher (264 kDa) than shrimp CHS and insect CHS protein. This difference was due to the presence of myosin motor head domain in the mollusk CHS protein (Zhang et al., 2021; Zheng et al., 2015). In the mollusk family, the first attempt at sequencing CHS gene was on A. rigida and M. galloprovincialis with a complete cDNA of the mussel CHS gene found in myosin motor head domain; however, this was not present in crustacean's and insects CHS gene (Weiss et al., 2006).…”

Isolation and characterization of a novel acidic matrix protein hic22 from the nacreous layer of the freshwater mussel, Hyriopsis cumingii

“…Perlucin is another important matrix protein of H. cumingii that is believed to induce pearl formation (Lin et al, 2013). Studies into the recently cloned HcCS1 gene have demonstrated its important role in shell formation via the regulation of chitin synthesis (Zheng et al, 2015). Silkmapin is another new matrix protein that has been shown to participate in the nucleation of calcium carbonate, providing nucleation sites to facilitate nacre formation .…”