Molecular characteristics of a novel HSP60 gene and its differential expression in Manila clams (Ruditapes philippinarum) under thermal and hypotonic stress

Abstract

The Manila clam Ruditapes philippinarum inhabits the intertidal zone and must therefore tolerate broad fluctuations in water temperature and salinity. Heat shock protein 60 (HSP60) is an evolutionarily conserved, multi-functional protein that plays a significant role in protecting organisms from harmful stress conditions. We cloned the R. philippinarum HSP60 (RpHSP60) gene and analyzed its transcriptional responses to thermal and low-salinity stresses. The complete sequence of RpHSP60 cDNA was 1777 nucleotides, containing a 1728-bp open reading frame encoding a polypeptide of 576-amino acids, with a calculated molecular mass of 61.25 kDa and predicted isoelectric point of 5.08. Comparisons of amino acid sequences and three-dimensional structures of HSP60 revealed that RpHSP60 was highly conserved in the signature HSP60-family domains. RpHSP60 mRNA was detected in all the tested tissues of R. philippinarum, with the highest expression levels in hemocytes. We measured RpHSP60 mRNA levels in the gills under thermal and low-salinity stresses using quantitative real-time reverse transcription-polymerase chain reaction. Following the thermal challenge, RpHSP60 mRNA was significantly upregulated at 6 h, and then progressively downregulated under high-temperature stress (30 °C), while only slight fluctuations were observed under low-temperature stress (-1 °C). Under low-salinity (17 ppt) stress, RpHSP60 mRNA levels were significantly increased at 3, 72, and 96 h (P < 0.05). These results suggest that HSP60 of R. philippinarum may play important roles in responding to high-temperature and low-salinity stresses.

Heat shock protein 60 expression and localisation in different tissues and testis development of male cattle (cattle-yak and yak)

“…Studies have shown that under low-salinity (17 ppt) stress, RpHSP60 mRNA levels were significantly increased at 3, 72, and 96 h (P < 0.05). These results suggest that HSP60 of R. philippinarum may play important roles in responding to high-temperature and low salinity stresses [34]. In addition, when hepatic cells were exposed by enrofloxacin, Hsp60 mRNA levels significantly increased in hepatocyte of ctenopharyngodon idellus [35].…”

Extracellular Vesicles and Post-Translational Protein Deimination Signatures in Mollusca—The Blue Mussel (Mytilus edulis), Soft Shell Clam (Mya arenaria), Eastern Oyster (Crassostrea virginica) and Atlantic Jacknife Clam (Ensis leei)

“…This indicates significantly suppressed stress and immunity response systems of oysters in longer term toxin exposure, compared with shorter term [96]. In Manila clam, HSP60 was found to play roles in response to low-salinity and high-temperature stresses [108]. In freshwater clams both HSP60 and HSP90 overexpression was associated with high thermal tolerance [111].…”

“…Heat shock proteins (HSP) 60 and 90 were identified as deiminated in blue mussel. HSP60 is a multifunctional evolutionarily conserved protein with stress-protective roles in organisms [108]. HSP90 participates in the protein folding response, cell cycle control, organism development, and the proper regulation of cytosolic proteins and cell damage during stress, including thermal stress and bacterial challenge in oysters [109].…”

Molecular response of a sub-antarctic population of the blue mussel (Mytilus edulis platensis) to a moderate thermal stress

“…Hsp60 (stress response), mt20 (detoxification) and HFI (O2 sensing) are overexpressed in individuals exposed to 20°C. Several studies have shown a regulation of Hsp60 mRNA expression in marine bivalves in response to increased temperature, without fully understanding its direct involvement in this response (Snyder et al, 2001;Ding et al, 2018). The other members of the HSP family studied here show either a significant decrease in expression (HSP24 and HSP90) or an absence of variation (HSC71, HSP22 and HSP78).…”