Identification and characterization of a heat shock protein 70 family member in channel catfish (Ictalurus punctatus).
We have determined the cDNA sequence of a member of the channel catfish heat shock protein 70 (CF Hsp70) family. This protein presumably functions as a molecular chaperone, as is characteristic of this family in other species. Channel catfish peripheral blood leukocytes exhibit a classical heat shock response, in that heat shock (37 degrees C) induces the expression of heat shock genes that are quiescent at normal temperatures (23 degrees C). It was observed that pre-existing synthesis of certain other molecules was suppressed (as evidenced by decreases in actin RNA upon heat shock). Similar trends were observed in mRNA expression for CF Hsp70 in two catfish non-leukocyte cell lines, channel catfish ovary and F59. However, three leukocyte cell lines constitutively expressed high levels of CF Hsp70 mRNA at optimal culture temperature (27 degrees C), whereas heat shock (37 degrees C) elicited only a modest induction of CF Hsp70 expression. Furthermore, continued investigation is warranted to determine whether the apparent upregulation of CF Hsp70 mRNA expression in the catfish long-term leukocyte cell lines is involved in the seemingly immortal phenotype of these cells.
Luft
J C
JC
Department of Microbiology, University of Mississippi Medical Center, Jackson 39216-4505, USA.
Wilson
M R
MR
Bly
J E
JE
Miller
N W
NW
Clem
L W
LW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D016384:Consensus Sequence; D018076:DNA, Complementary / Q000235:genetics*; D015698:Genomic Library; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis* / Q000235:genetics; D007059:Ictaluridae / Q000378:metabolism*; D008969:Molecular Sequence Data; D012016:Reference Values; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D018076:DNA, Complementary; D018840:HSP70 Heat-Shock Proteins