High impact information on MtnB

• The gene corresponding to our MT cDNA (Mto) is inducible in Drosophila cell lines and in both larval and adult flies [1].
• The pattern of expression of Mto suggests that this gene may be involved in the control of metal homeostasis during development [2].
• Transcription of Mto is detected early in embryogenesis (0 to 3 h) and persists to the third larval instar, while Mtn expression starts later in embryogenesis (12 to 15 h) and is thereafter maintained throughout larval development and adult stages [2].
• Using various reporter gene constructs and mRNA quantification, we show that the MtnA promoter is preferentially induced by copper, while the MtnB promoter is preferentially induced by cadmium [3].
• Interestingly, experimental data only showed minor differences in the coordinative behavior of both MTs, but provided a characteristic spectroscopic fingerprint, revealing the possible binding of chloride anions in certain metal-MTO aggregates [4].

Biological context of MtnB

• Functions of MTN and MTO proteins in metal homeostasis and detoxification are considered [5].
• Mtn and Mto transcripts were detected exclusively in the digestive tract of larvae, pupae and adults reared on standard medium [5].
• Mtn gene expression is induced by these three metals in Malpighian tubules, while Mto gene expression in this organ is induced only by zinc [5].
• Mtn and Mto transgenes respond differently to metallic, heat-shock and oxidative stresses.These data confirm that both genes are in part functionally different [6].
• In order to compare the properties of Mto and Mtn, we transformed yeast with several fusion plasmids [7].

Associations of MtnB with chemical compounds

• Such a metal preference is also observed at the protein level as the stoichiometric, spectrometric and spectroscopic features of the copper and cadmium complexes with MtnA and MtnB correlate well with a greater stability of copper-MtnA and cadmium-MtnB [3].
• Chloride and Sulphide ligands have been detected in Zn- and Cd-MtnB aggregates by means of Raman end Circular Dichroism spectroscopy [8].

Analytical, diagnostic and therapeutic context of MtnB

• Expression of the two Drosophila melanogaster metallothionein genes, Mtn and Mto, has been analyzed by in situ hybridization during post-embryonic development [5].
• The metal binding abilities of the Cu- and Zn-MTN complexes conformed in vivo, as well as the features of the Cd- and Cu-aggregates produced by metal replacement in vitro, have been determined by atomic emission spectrometry, circular dichroism and electrospray ionization mass spectrometry [9].

References