title: Identification of members of the HSP30 small heat shock protein family and characterization of their developmental regulation in heat-shocked Xenopus laevis embryos.
abstract: In the present study we have characterized the synthesis of members of the HSP30 family during Xenopus laevis development using a polyclonal antipeptide antibody derived from the carboxyl end of HSP30C. Two-dimensional PAGE/immunoblot analysis was unable to detect any heat-inducible small HSPs in cleavage, blastula, gastrula, or neurula stage embryos. However, heat-inducible accumulation of a single protein was first detectable in early tailbud embryos with an additional 5 HSPs at the late tailbud stage and a total of 13 small HSPs at the early tadpole stage. In the Xenopus A6 kidney epithelial cell line, a total of eight heat-inducible small HSPs were detected by this antibody. Comparison of the pattern of protein synthesis in embryos and somatic cells revealed a number of common and unique heat inducible proteins in Xenopus embryos and cultured kidney epithelial cells. To specifically identify the protein product of the HSP30C gene, we made a chimeric gene construct with the Xenopus HSP30C coding sequence under the control of a constitutive promoter. This construct was microinjected into fertilized eggs and resulted in the premature and constitutive synthesis of the HSP30C protein in gastrula stage embryos. Through a series of mixing experiments, we were able to specifically identify the protein encoded by the HSP30C gene in embryos and somatic cells and to conclude that HSP30C synthesis was first head-inducible at the early tailbud stage of development. The differential pattern of heat-inducible accumulation of members of the HSP30 family during Xenopus development suggests that these proteins may have distinct functions at specific embryonic stages during a stress response.
authors.affiliation: Department of Biology, University of Waterloo, Ontario, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Tam
authors.forename: J J
authors.initials: JJ
authors.lastname: Heikkila
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D005260:Female; D018507:Gene Expression Regulation, Developmental; D050890:HSP30 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D011817:Rabbits; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: D050890:HSP30 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D029867:Xenopus Proteins; C494391:hsp30 protein, Xenopus