title: The Gln32Lys polymorphism in HSP22 of Zhikong scallop Chlamys farreri is associated with heat tolerance.
abstract: BACKGROUND
  Heat shock protein 22 is a member of small heat shock proteins with molecular chaperone activity. Though their multiple functions have been well characterized, there is no report about the association between the polymorphisms of HSP22 and heat tolerance.
  
  
  METHODS
  Three single nucleotide polymorphisms were identified in HSP22 from scallop Chlamys farreri (CfHSP22), and the +94 C-A locus was found to be nonsynonymous. Three genotypes at locus +94, A/A, A/C and C/C, were revealed by using Bi-PASA PCR analysis, and their frequencies were 19.5%, 27.6% and 52.9% in the heat resistant stock, while 9.3%, 17.4% and 73.3% in the heat susceptible stock, respectively. The frequency differences of the three genotypes were significant (P<0.05) between the two stocks. After incubating at 30°C for 84 h, the cumulative mortality of scallops with +94 C/C genotype and +94 A/C genotypes was 95% and 90%, respectively, which was significantly higher (P<0.01) than that of scallops with +94 A/A genotype (70%). The molecular chaperone activity of two His-tagged fusion proteins, rCfHSP22Q with +94 C/C genotype and rCfHSP22K with +94 A/A genotype were analyzed by testing the ability of protecting citrate synthase (CS) against thermal inactivation in vitro. After incubated with rCfHSP22Q or rCfHSP22K at 38°C for 1 h, the activity of CS lost 50% and 45%, and then recovered to 89% and 95% of the original activity following 1 h restoration at 22°C, respectively, indicating that the mutation from Gln to Lys at this site might have an impact on molecular chaperone activities of CfHSP22.
  
  
  CONCLUSIONS
  These results implied that the polymorphism at locus +94 of CfHSP22 was associated with heat tolerance of scallop, and the +94 A/A genotype could be a potential marker available in future selection of Zhikong scallop with heat tolerance.
authors.affiliation: The Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese 7 Academy of Sciences, Qingdao, China.
authors.forename: Chuanyan
authors.initials: C
authors.lastname: Yang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Lingling
authors.initials: L
authors.lastname: Wang
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.forename: Limei
authors.initials: L
authors.lastname: Qiu
authors.forename: Vinu S
authors.initials: VS
authors.lastname: Siva
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D002950:Citrate (si)-Synthase / Q000235:genetics; D005819:Genetic Markers; D005838:Genotype; D005973:Glutamine / Q000737:chemistry*; D050888:Heat-Shock Proteins, Small / Q000235:genetics* / Q000502:physiology; D006358:Hot Temperature; D008239:Lysine / Q000737:chemistry*; D018832:Molecular Chaperones / Q000378:metabolism; D008969:Molecular Sequence Data; D049897:Pectinidae; D011110:Polymorphism, Genetic; D011994:Recombinant Proteins / Q000235:genetics; D013997:Time Factors
chemical_list: D005819:Genetic Markers; D050888:Heat-Shock Proteins, Small; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D005973:Glutamine; D002950:Citrate (si)-Synthase; D008239:Lysine