UEDA, N.*; BOETTCHER, A.A.; Univ. of South Alabama; Univ. of South Alabama: Variations in Heat Shock Protein 70 Expression Among Developmental Stages and Tissue Types in Crassostrea virginica

Developmental regulation of heat shock protein (HSP) expression has been reported for insect, plant, teleost, avian, and mammalian species. In many cases, significant changes in expression occur during metamorphosis and may be linked to cellular differentiation during this process. HSPs are molecular chaperones that aid in the proper folding of proteins and are known to play a role in normal cell processes and in response to environmental stress. Two types of HSPs have been identified, constitutively expressed forms (HSCs) which may support translocation of newly synthesized polypeptides and stress inducible forms (HSPs) which are involved in re-folding of damaged proteins in the cells. Despite reports from diverse taxonomic groups, little is known about developmental regulation of HSPs in marine invertebrates. In this study, differences in expression patterns of HSP 70 in eastern oyster, Crassostrea virginica larvae and spat as well as among adult tissue types were examined. C. virginica expresses three isoforms of HSP 70; two constitutive forms (HSC 77 and 72) and one inducible form (HSP 69). There were differences in the expression of the isoforms among larval and spat samples and among adult tissue types. HSC 77 and HSC 72 were detected in all larval and spat samples. Both were down-regulated during larval development, and increased in later stage spat. HSP 69 was not detected in either larval or spat samples. All three HSP 70 isoforms were found in adult tissue. Mantle and gill tissue had higher expression levels of all three isoforms than did adductor muscle tissue. Further investigations will be focused on the relationship between HSP expression and cellular differentiation during development.