Transcriptional responses of metallothionein gene to different stress factors in Pacific abalone ( Haliotis discus hannai )

Molecular cloning of metal-responsive transcription factor-1 (MTF-1) and transcriptional responses to metal and heat stresses in Pacific abalone, Haliotis discus hannai

“…However, the expression pattern observed in this study was generally in congruent with the anticipated roles of MTF-1 in embryonic and early ontogenic developments, as inferred from mammalian and teleostean cases (Günes et al 1998;Chen et al 2002;Chen et al 2007). The expression pattern of MTF-1 during the development was also in agreement with the modulation pattern of its primary target (e.g., MT) in the same abalone species (Lee and Nam 2016a). Previously, the functional involvements of MTF-1 in the development and organogenesis have been highlighted by the lethality of "MTF-1-knockout" mice (Günes et al 1998;Wang et al 2004) and by induced inhibition of MTF-1 signaling followed by transcriptomic profiling in zebrafish embryos (O'Shields et al 2014).…”

“…The heavy metals used for exposure were of analytical grade reagents (Sigma-Aldrich, St. Louis, MO, USA). After 24 h, two tanks were treated with 0.02 mg/L (i.e., 20 ppb) and 0.1 mg/L (i.e., 100 ppb) cadmium (Cd), while two tanks with 20 and 100-ppb zinc (Zn) (Lee and Nam 2016a). Nominal concentration of the metal for each metal-exposed group was adjusted by using CdC1 2 or ZnCl 2 stock solution.…”

“…Thermal cycling condition for each gene (i.e., MTF-1 and normalization control genes) can be referred to Additional file 1: Table S1. Based on our preliminary study to evaluate candidate housekeeping genes for the normalization of RT-qPCR amplification (unpublished data; see also (Lee and Nam 2016a;Lee and Nam 2016b)), abalone ribosomal proteins L5 (RPL5; ABO26701) and L7 (RPL7; KP698945) genes were used as reference genes to normalize expression levels of MTF-1 transcripts in tissue samples (i.e., for basal tissue expression assays and stress exposure treatments), while RPL7 and RPL8 (KP698947) were used to normalize MTF-1 expression across developmental samples (embryos and larvae). Additionally, for heavy-metal exposure groups, the messenger RNA (mRNA) expression levels of MTF-1 were compared with those of MT (the known target gene of MTF-1) in order to examine whether or not there might be any positive or proportional relationship in the metalmediated modulation patterns between MTF-1 and MT genes.…”

“…In mouse, the reason for the high MTF-1 expression in testis has been explained by that sexually mature mice need to accumulate a large quantity of MTs in their testes (Auf der Maur et al 2000;De et al 1991). However, this hypothesis is unlikely to be adopted to this abalone species since the virtual increase of MT expression in sexually mature abalones has been observed in ovary rather than in testis (Lee and Nam 2016a), suggesting the molecular mechanism for the boosted expression of MTF-1 in abalone testis might be distinct from the ones in mammals. Hence, further study to monitor the MTF-1 expression in line with the testis development and Figure S4 maturation cycle would be valuable to get a deeper insight into this phenomenon.…”

“…However, despite its importance, adaptive or defensive functions to such environmental perturbations have been limitedly investigated in this abalone species, and almost no information has been available with respect to the coordinated regulations of genes involved in cellular pathways associated with metal regulation and oxidative stress responses (Kim et al 2007;Lee and Nam 2016a). For this reason, understanding of MTF-1 from abalone species would be much useful to better comprehend orchestrated and coordinated regulations of host defense genes in this abalone species.…”