Characterization of a novel group of basic small heat shock proteins in Xenopus laevis A6 kidney epithelial cells.
In this study, we report the detection of a new group of five stress-inducible basic small heat shock proteins (BShsps) in Xenopus laevis kidney epithelial A6 cells by means of two-dimensional non-equilibrium pH gradient gel electrophoresis. These basic 30-kDa small hsps are distinct from the previously described X. laevis acidic hsp30 family on the basis of their charge and lack of cross-reactivity with an hsp30 antibody. Furthermore, at least two of the five BShsps were present constitutively, an observation that has not been made with the acidic hsp30 family. The heat inducibility of the BShsps was regulated at the level of transcription as indicated by their inhibited synthesis in the presence of the transcriptional inhibitor actinomycin D. Furthermore, the optimal temperature of BShsp induction, temporal pattern of synthesis, and induction of BShsps by other stressors such as herbimycin A and sodium arsenite were similar to those reported for the acidic hsp30 family. This study suggests that X. laevis contains at least two unique groups of small heat shock proteins that are coordinately expressed.
Ohan
N W
NW
Department of Biology, University of Waterloo, ON, Canada.
Tam
Y
Y
Fernando
P
P
Heikkila
J J
JJ
D000818:Animals; D018053:Arsenites / Q000494:pharmacology; D016227:Benzoquinones; D015152:Blotting, Northern; D002478:Cells, Cultured; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D047029:Lactams, Macrocyclic; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011809:Quinones / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D017670:Sodium Compounds / Q000494:pharmacology; D014981:Xenopus / Q000378:metabolism*
D018053:Arsenites; D016227:Benzoquinones; D004791:Enzyme Inhibitors; D006360:Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D011500:Protein Synthesis Inhibitors; D011809:Quinones; D017670:Sodium Compounds; D003609:Dactinomycin; D017828:Rifabutin; C017947:sodium arsenite; C020754:herbimycin