R. Scudiero et al., Tissue-specific regulation of metallothionein and metallothionein mRNA accumulation in the Antarctic notothenioid, Notothenia coriiceps, POLAR BIOL, 23(1), 2000, pp. 17-23
The distribution of metallothionein and metallothionein mRNA was examined i
n brain, liver and kidney of the red-blooded Antarctic fish Notothenia cori
iceps. Basal levels of metallothionein were detected by silver saturation a
ssay; the analysis showed large differences in the metallothionein content,
with an increasing amount in kidney, liver and brain, respectively. Revers
e transcriptase-mediated polymerase chain reaction was used to amplify two
distinct metallothionein cDNA species from RNA extracted from the three tis
sues examined. Northern blot analysis revealed a high constitutive expressi
on of metallothionein mRNA in kidney, in spite of the low metallothionein c
ontent found in this tissue. The analysis of the distribution of the two me
tallothionein transcripts, termed MT-1 and MT-2, in the tissues showed that
the MT-2 transcript was the major form of the metallothionein mRNA in kidn
ey and brain, whilst in liver the expression levels of the two metallothion
ein transcripts were comparable. This tissue-specific expression of isometa
llothioneins in the Antarctic fish suggests the presence of an organ-specif
ic regulation of the metallothionein genes.