IDENTIFICATION OF HEAVY-METAL INDUCED CHANGES IN THE EXPRESSION PATTERNS OF THE TRANSLATIONALLY CONTROLLED TUMOR PROTEIN (TCTP) IN THE EARTHWORM LUMBRICUS-RUBELLUS
Sr. Sturzenbaum et al., IDENTIFICATION OF HEAVY-METAL INDUCED CHANGES IN THE EXPRESSION PATTERNS OF THE TRANSLATIONALLY CONTROLLED TUMOR PROTEIN (TCTP) IN THE EARTHWORM LUMBRICUS-RUBELLUS, Biochimica et biophysica acta, N. Gene structure and expression, 1398(3), 1998, pp. 294-304
Heavy metal contaminated soils are assessed for specific human health
and ecological risk by governmental regulatory agencies utilizing the
abundant soil invertebrate, the earthworm, in a biomonitoring process.
Fingerprinting the molecular genetic responses resulting from heavy m
etal exposure facilitates the identification of biomarkers for assessi
ng the impact of such pollution on individual organisms. This paper re
ports the identification of a novel translationally controlled tumour
protein (TCTP) in the earthworm Lumbricus rubellus. In addition to the
standard molecular biological technique of differential Southern blot
ting, a fully quantitative approach (fluorescent microvolume PCR) was
performed to assess the specific expression profiles of TCTP in earthw
orms exposed to different heavy metal regimes. After normalizing with
actin as an invariant control, the results showed that TCTP was upregu
lated by at least a factor of 4 in the population originating from a P
b/Zn/Cd polluted mine, compared to an unpolluted control population. A
n even more pronounced increase was identified in earthworms native to
a Cu polluted mine, where TCTP increased 335-fold. TCTP copies in ear
thworms exposed to artificial soil with a single stressor (Cd) were 14
times higher than in the appropriate control earthworms (maintained o
n artificial soil without Cd). The data presented are novel in two way
s: first, they provide evidence for an upregulation that is induced by
heavy metals (especially copper); second, they show that TCTP can als
o be under transcriptional control, therefore upregulation is not limi
ted to translational modifications as TCTP's nomenclature suggests. (C
) 1998 Elsevier Science B.V. All rights reserved.