INDUCTION OF GENE-EXPRESSION OF THE CHAPERONE-14-3-3 AND CHAPERONE-HSP70 BY PCB-118-(2,3',4,4',5-PENTACHLORO-BIPHENYL) IN THE MARINE SPONGEGEODIA-CYDONIUM - NOVEL BIOMARKERS FOR POLYCHLORINATED-BIPHENYLS
M. Wiens et al., INDUCTION OF GENE-EXPRESSION OF THE CHAPERONE-14-3-3 AND CHAPERONE-HSP70 BY PCB-118-(2,3',4,4',5-PENTACHLORO-BIPHENYL) IN THE MARINE SPONGEGEODIA-CYDONIUM - NOVEL BIOMARKERS FOR POLYCHLORINATED-BIPHENYLS, Marine ecology. Progress series, 165, 1998, pp. 247-257
Polychlorinated biphenyls (PCBs) are ubiquitous industrial compounds f
ound in almost every component of the terrestrial and marine ecosystem
. Most of the PCB congeners bind to the aryl hydrocarbon receptor and
in turn cause expression of stress response genes. Here we report for
the first time that PCB 118 acts in the marine sponge Geodia cydonium
as an inducer of 2 chaperones, the 14-3-3 protein(s) (a protein target
ing molecule) and the heat shock protein HSP70 (a chaperone, primarily
involved in folding of proteins). While the cDNA encoding the latter
protein has been cloned previously, the 14-3-3 cDNA from sponges is re
ported in this study. The full-length cDNA clone of G. cydonium, GC14-
3-3, has a size of 912 nucleotides (nt) and contains a 744 nt long pot
ential open reading frame; the relative molecular weight (M-r) of the
deduced aa sequence is 28 378 Da. The sponge polypeptide is closely re
lated to the deduced polypeptides of the 14-3-3 sequences belonging to
isoforms eta and gamma. Using the cDNAs, coding for the 14-3-3 and th
e HSP70 proteins as well as antibodies raised against these 2 proteins
, it was demonstrated that neither chaperone can be detected in the ab
sence of PCB. However, after incubation of sponge tissue with PCB 118
the transcripts of the 2 chaperones are detectable after 12 h, while t
he corresponding proteins appear after 1 d. Subsequently, the levels o
f the transcripts and of the proteins increase steadily. From these da
ta we conclude that the 2 chaperones, 14-3-3 and HSP70, are useful bio
markers in sponges. Due to the broad cross-reactivity of their antibod
ies throughout the Metazoa, these chaperones may be useful biomarkers
for monitoring environmental contaminants, as shown here for PCB 118,
in all organisms.