Biochemical Characterization and Quantitative Gene Expression Analysis of the Multi-Stress Inducible Metallothionein from Tetrahymena thermophila

Cloning and Characterization of a New Multi-Stress Inducible Metallothionein Gene in Tetrahymena pyriformis

“…Additionally, one ATTTA and one TTTT motif, which were suggested to function in rapid degradation of certain short-lived mRNAs as revealed in mammals, have been found in the 3 0 -UTR of the TpMT-2 gene. This is consistent with cases described in most of the other Tetrahymena MT genes (Dondero et al 2004;Piccinni et al 1999;Santovito et al 2001).…”

“…Those isoforms differ from all MTs reported in other organisms, since the arrangement of Cys residues between them showed only limited similarities (Boldrin et al 2003). Previous studies indicated that the MTs of Tetrahymena not only play a role in heavy metal homeostasis and detoxification, but also respond to a wide variety of stimulants, from chemical to physical and biological ones, at the regulation and expression level (Boldrin et al 2002;Dondero et al 2004). However, both the functional significance of the multiple MT isoforms that exist among different Tetrahymena species and the genetic mechanisms involved in the formation of the peculiar MT genes have not been fully clarified.…”

“…2). This ''universal'' poly A signal, however, has not been found in other Tetrahymena MT genes wherein signals different by one residue (AATTAA or ATAAAA) were the putative functional ones (Boldrin et al 2003;Dondero et al 2004). Additionally, one ATTTA and one TTTT motif, which were suggested to function in rapid degradation of certain short-lived mRNAs as revealed in mammals, have been found in the 3 0 -UTR of the TpMT-2 gene.…”

Cloning, characterization, and gene expression analysis of a novel cadmium metallothionein gene in Tetrahymena pigmentosa

“…The AATATA at nt 457-462 in the 3′UTR of Tpig-MT1 gene, 56 nt before the poly A tail, differs by only one residue from the usual eukaryotic organisms polyadenylation signal and has not been shown in other MT genes. A "TTTT" motif reported in other Tetrahymena MT genes (Piccinni et al, 1999;Santovito et al, 2001;Dondero et al, 2004;Fu and Miao, 2006), which was suggested to function in rapid degradation of certain short-lived mRNAs as revealed in mammals, was also found in Tpig-MT1 gene 3′ UTR. However, since the average GC content of the Tetrahymena genome is 22% and intergenic sequences tend to be even more ATrich (Eisen et al, 2006), such AT-rich motifs are easily found throughout the genome.…”

“…The biological functions of the ciliate MT can be inferred by gene expression analysis (Dondero et al, 2004), albeit indirectly. Tetrahymena MTs are proposed to function in both heavy metal homeostasis and detoxification, and different isoforms exhibit unique expression patterns in response to exposure to different metals (Boldrin et al, 2002).…”