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Troponin T isoform expression is modulated during Atlantic halibut metamorphosis.

Campinho MA, Silva N, Nowell MA, Llewellyn L, Sweeney GE, Power DM - BMC Dev. Biol. (2007)

Bottom Line: In contrast, expression of red muscle specific genes, AfTnT and sTnT2, did not change during natural metamorphosis or after T4 treatment.Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations.We hypothesize that species specific differences in TnT gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.

View Article: PubMed Central - HTML - PubMed

Affiliation: CCMAR, FERN, Universidade do Algarve, Campus de Gambelas, Faro, Portugal. macampin@ualg.pt <macampin@ualg.pt>

ABSTRACT

Background: Flatfish metamorphosis is a thyroid hormone (TH) driven process which leads to a dramatic change from a symmetrical larva to an asymmetrical juvenile. The effect of THs on muscle and in particular muscle sarcomer protein genes is largely unexplored in fish. The change in Troponin T (TnT), a pivotal protein in the assembly of skeletal muscles sarcomeres and a modulator of calcium driven muscle contraction, during flatfish metamophosis is studied.

Results: In the present study five cDNAs for halibut TnT genes were cloned; three were splice variants arising from a single fast TnT (fTnT) gene; a fourth encoded a novel teleost specific fTnT-like cDNA (AfTnT) expressed exclusively in slow muscle and the fifth encoded the teleost specific sTnT2. THs modified the expression of halibut fTnT isoforms which changed from predominantly basic to acidic isoforms during natural and T4 induced metamorphosis. In contrast, expression of red muscle specific genes, AfTnT and sTnT2, did not change during natural metamorphosis or after T4 treatment. Prior to and after metamorphosis no change in the dorso-ventral symmetry or temporal-spatial expression pattern of TnT genes and muscle fibre organization occurred in halibut musculature.

Conclusion: Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations. We hypothesize that species specific differences in TnT gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.

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Effect of T4 treatment on halibut TnT genes expression in pre-metamorphic larvae; Ethidium bromide gels showing expression of fTnThh (A), AfTnThh (B), sTnT2hh (C) and 18s rRNA genes in pre-metamorphic larvae treated for 10 days with T4 or untreated (control). Graphs on the right side of gel images represent fTnThh and AfTnThh isoform expression and sTnT2hh expression in relation of 18s rRNA in control and T4 treated pre-metamorphic (stg 5) halibut larvae for 10 days. *- represents significant statistical differences between efTnThh expression in control and T4 treated halibut larvae (HSD, p < 0.05). No reference signifies no significant statistical difference (HSD, p > 0.05).
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Figure 11: Effect of T4 treatment on halibut TnT genes expression in pre-metamorphic larvae; Ethidium bromide gels showing expression of fTnThh (A), AfTnThh (B), sTnT2hh (C) and 18s rRNA genes in pre-metamorphic larvae treated for 10 days with T4 or untreated (control). Graphs on the right side of gel images represent fTnThh and AfTnThh isoform expression and sTnT2hh expression in relation of 18s rRNA in control and T4 treated pre-metamorphic (stg 5) halibut larvae for 10 days. *- represents significant statistical differences between efTnThh expression in control and T4 treated halibut larvae (HSD, p < 0.05). No reference signifies no significant statistical difference (HSD, p > 0.05).

Mentions: Treatment of pre-metamorphic halibut larvae for 10 days with T4 totally repressed efTnThh isoform expression (HSD, p < 0.05, Fig. 11A) without affecting the expression of the other two fTnThh isoforms (HSD, p > 0.05, Fig. 11A). Neither AfTnThh or sTnT2hh expression or isoform profile is altered from that of control larvae by T4 treatment (Fig 11B and 11C).


Troponin T isoform expression is modulated during Atlantic halibut metamorphosis.

Campinho MA, Silva N, Nowell MA, Llewellyn L, Sweeney GE, Power DM - BMC Dev. Biol. (2007)

Effect of T4 treatment on halibut TnT genes expression in pre-metamorphic larvae; Ethidium bromide gels showing expression of fTnThh (A), AfTnThh (B), sTnT2hh (C) and 18s rRNA genes in pre-metamorphic larvae treated for 10 days with T4 or untreated (control). Graphs on the right side of gel images represent fTnThh and AfTnThh isoform expression and sTnT2hh expression in relation of 18s rRNA in control and T4 treated pre-metamorphic (stg 5) halibut larvae for 10 days. *- represents significant statistical differences between efTnThh expression in control and T4 treated halibut larvae (HSD, p < 0.05). No reference signifies no significant statistical difference (HSD, p > 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1919359&req=5

Figure 11: Effect of T4 treatment on halibut TnT genes expression in pre-metamorphic larvae; Ethidium bromide gels showing expression of fTnThh (A), AfTnThh (B), sTnT2hh (C) and 18s rRNA genes in pre-metamorphic larvae treated for 10 days with T4 or untreated (control). Graphs on the right side of gel images represent fTnThh and AfTnThh isoform expression and sTnT2hh expression in relation of 18s rRNA in control and T4 treated pre-metamorphic (stg 5) halibut larvae for 10 days. *- represents significant statistical differences between efTnThh expression in control and T4 treated halibut larvae (HSD, p < 0.05). No reference signifies no significant statistical difference (HSD, p > 0.05).
Mentions: Treatment of pre-metamorphic halibut larvae for 10 days with T4 totally repressed efTnThh isoform expression (HSD, p < 0.05, Fig. 11A) without affecting the expression of the other two fTnThh isoforms (HSD, p > 0.05, Fig. 11A). Neither AfTnThh or sTnT2hh expression or isoform profile is altered from that of control larvae by T4 treatment (Fig 11B and 11C).

Bottom Line: In contrast, expression of red muscle specific genes, AfTnT and sTnT2, did not change during natural metamorphosis or after T4 treatment.Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations.We hypothesize that species specific differences in TnT gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.

View Article: PubMed Central - HTML - PubMed

Affiliation: CCMAR, FERN, Universidade do Algarve, Campus de Gambelas, Faro, Portugal. macampin@ualg.pt <macampin@ualg.pt>

ABSTRACT

Background: Flatfish metamorphosis is a thyroid hormone (TH) driven process which leads to a dramatic change from a symmetrical larva to an asymmetrical juvenile. The effect of THs on muscle and in particular muscle sarcomer protein genes is largely unexplored in fish. The change in Troponin T (TnT), a pivotal protein in the assembly of skeletal muscles sarcomeres and a modulator of calcium driven muscle contraction, during flatfish metamophosis is studied.

Results: In the present study five cDNAs for halibut TnT genes were cloned; three were splice variants arising from a single fast TnT (fTnT) gene; a fourth encoded a novel teleost specific fTnT-like cDNA (AfTnT) expressed exclusively in slow muscle and the fifth encoded the teleost specific sTnT2. THs modified the expression of halibut fTnT isoforms which changed from predominantly basic to acidic isoforms during natural and T4 induced metamorphosis. In contrast, expression of red muscle specific genes, AfTnT and sTnT2, did not change during natural metamorphosis or after T4 treatment. Prior to and after metamorphosis no change in the dorso-ventral symmetry or temporal-spatial expression pattern of TnT genes and muscle fibre organization occurred in halibut musculature.

Conclusion: Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations. We hypothesize that species specific differences in TnT gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.

Show MeSH
Related in: MedlinePlus