Enzymatic control of anhydrobiosis-related accumulation of trehalose in the sleeping chironomid, Polypedilum vanderplanki.
Bottom Line: Although computational prediction indicated that the alternative splicing variants (PvTpsα/β) obtained encoded probable functional motifs consisting of a typical consensus domain of TPS and a conserved sequence of TPP, PvTpsα did not exert activity as TPP, but only as TPS.Trehalose was synthesized abundantly, consistent with increased activities of TPS and TPP and suppressed TREH activity.These results show that trehalose accumulation observed during anhydrobiosis induction in desiccating larvae can be attributed to the activation of the trehalose synthetic pathway and to the depression of trehalose hydrolysis.
Affiliation: Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.Show MeSH
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Mentions: As shown in Fig. 1B, in P. vanderplanki, trehalose is likely to be synthesized from glycogen en route to anhydrobiosis. In eukaryotes, the metabolic pathway from glycogen to trehalose is highly conserved (Fig. 1A). Hence, in order to elucidate the molecular mechanisms underlying the regulation of the enzymes involved in trehalose metabolism on desiccation, we first investigated the expression profiles of PvTpsα/β, PvTpp and PvTreh mRNAs (Fig. 6A). The accumulation of PvTpsα/β and PvTpp mRNAs was induced within 1 h and 3 h, respectively, during desiccation treatment. For PvTreh, the induction of mRNA accumulation was delayed by 48 h after the beginning of desiccation treatment compared with the other two genes. Real-time PCR analyses of these mRNAs confirmed the results (data not shown). However, the amount of PvGp mRNAs remained constant during treatment, which is consistent with the constancy of GP activity on desiccation (Fig. 2A). Western blot analyses revealed that the proteins of PvTPSα/β, PvTPP and PvTREH were also accumulated, as were the corresponding mRNAs (Fig. 6B).
Affiliation: Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.