Functional genomic characterization of metallothioneins in brown trout (Salmo trutta L.). using synthetic genetic analysis

Abstract

Metal pollution has made a significant impact on the earth’s ecosystems and tolerance to metals in a wide variety of species has evolved. Metallothioneins, a group of cysteine-rich metal-ion binding proteins, are known to be a key physiological mechanism in regulating protection against metal toxicity. Many rivers across the southwest of England are detrimentally affected by metal pollution, but brown trout ( Salmo trutta L.) populations are known to reside within them. In this body of work, two isoforms of metallothionein ( MetA and MetB ) isolated from trout occupying a polluted and a control river are examined. Using synthetic genetic array (SGA) analyses in the model yeast, Saccharomyces cerevisiae , functional genomics is used to explore the role of metallothionein isoforms in driving metal tolerance. By harnessing this experimental system, S. cerevisiae is used to (i) determine the genetic interaction maps of MetA and MetB isoforms; (ii) identify differences between the genetic interactions in both isoforms and (iii) demonstrate that pre-exposure to metals in metal-tolerant trout influences these interactions. By using a functional genomics approach leveraged from the model yeast Saccharomyces cerevisiae , we demonstrate how such approaches could be used in understanding the ecology and evolution of a non-model species.

Comparison of intracellular trace element distributions in the liver and gills of the invasive freshwater fish species, Prussian carp (Carassius gibelio Bloch, 1782)

“…In a conclusion, MTs have been shown to play an important role in the detoxification of metals in fish (Paris and Usher, 2019). And, based on our results, both studied organs obviously participated in the detoxification of toxic element Cd, gills as a site of direct contact and uptake of pollutants, and thus the first line of defense, and the liver as the main storage and detoxification organ, preventing the long term toxic effects.…”

“…These peaks corresponded well with the peak of MT standard, which was, under the same conditions, eluted in 31 st minute (Table 3). MTs are a family of low molecular mass, cysteine-rich proteins (up to 30% of their constituent aminoacids), which have the capacity to bind both essential metals, like Cu and Zn, and nonessential metals, like As and Cd, by the thiol groups of their cysteine residues (Paris and Usher, 2019). In the liver of Prussian carp, the elution in MT region was very clear, with sharp peaks, for all three metals (Figs.…”

“…And, based on our results, both studied organs obviously participated in the detoxification of toxic element Cd, gills as a site of direct contact and uptake of pollutants, and thus the first line of defense, and the liver as the main storage and detoxification organ, preventing the long term toxic effects. On the other hand, MTs also have important role in essential metal ion homeostasis (Paris and Usher, 2019), such as Cu and Zn (Olsson, 1996). It is known that Zn can be held in MT reserves and that Zn-binding by MTs contribute to maintainance of intracellular Zn levels (Osredkar and Sustar, 2011).…”