Molecular cloning of a cDNA encoding a Xenopus laevis 70-kDa heat shock cognate protein, hsc70.II.
We have isolated and sequenced a full-length cDNA clone encoding a Xenopus laevis 70 kDa heat shock cognate protein, hsc70.II. The protein coding region exhibited high identity with Xenopus hsc70.I (94%), suggesting that the two genes are the result of a genomic tetraploidization event which occurred in Xenopus over 30 million years ago. Also, hsc70.II displayed a high level of identity with mammalian hsc70. However, the identity of Xenopus hsc70.II cDNA with Xenopus hsp70 was only 82%. At the carboxyl end of the hsc70.II protein, the identity with hsc70.I was 85%, while the identity for hsp70 was only 58%. These data support the theory that the inducible and constitutive members of the hsp70 family diverged well before the emergence of amphibians. Also, hsc70.II contains a number of conserved elements including an ATP-binding domain, a nuclear localization signal and the carboxyl terminal motif, EEVD, which may have a role in chaperone function.
Ali
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A
Department of Biology, University of Waterloo, ON, Canada.
Salter-Cid
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Flajnik
M J
MJ
Heikkila
J J
JJ
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry*; D016208:Databases, Factual; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D015800:Protozoan Proteins / Q000737:chemistry; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D029867:Xenopus Proteins; D014982:Xenopus laevis
D018076:DNA, Complementary; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C490436:Heat shock cognate protein 70, Xenopus; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D015800:Protozoan Proteins; D029867:Xenopus Proteins; C081884:heat-shock protein 70.1; D000255:Adenosine Triphosphate