A. Ali et al., MOLECULAR-CLONING OF A CDNA-ENCODING A XENOPUS-LAEVIS 70-KDA HEAT-SHOCK COGNATE PROTEIN, HSC70.II, Biochimica et biophysica acta, N. Gene structure and expression, 1309(3), 1996, pp. 174-178
We have isolated and sequenced a full-length cDNA clone encoding a Xen
opus laevis 70 kDa heat shock cognate protein, hsc70.II. The protein c
oding region exhibited high identity with Xenopus hsc70.I (94%), sugge
sting that the two genes are the result of a genomic tetraploidization
event which occurred in Xenopus over 30 million years ago. Also, hsc7
0.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 supp
ort the theory that the inducible and constitutive members of the hsp7
0 family diverged well before the emergence of amphibians. Also, hsc70
.II contains a number of conserved elements including an ATP-binding d
omain, a nuclear localization signal and the carboxyl terminal motif,
EEVD, which may have a role in chaperone function.