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Functional study of N-acetyltransferase 1 (TcNAT1) involved in cuticle tanning pathway in the red flour beetle, Tribolium castaneum
- 언어ENG
- URLhttps://db.koreascholar.com/Article/Detail/287903
Insect cuticle/exoskeleton is a first physical barrier to protect their body from multifarious environments such as desiccation, natural enemies and entomopathogenic microorganisms. Cuticle tanning (sclerotization and pigmentation) is a vital procedure for generating suitable cuticle depending on body region by sclerotization and pigmentation in insects.
Insect cuticle tanning is a complex process involves hydroxylation of tyrosine to 3,4-dihydroxyphenylalanine (DOPA), decarboxylation of DOPA to dopamine, N-acylation of dopamine to N-acetyldopamine (NADA) or N-β-alanyldopamine (NBAD), oxidation of NADA and NBAD to their corresponding quinones, and reactions between the quinones or quinone derivatives with cuticle protein (CP) side chains resulting in protein cross-linking. One type of pigmentation (quinone tanning) is associated with the covalent linkage of CPs to the ring component of NBAD. In contrast, linkage of CPs to the side chain of NADA (b-sclerotization) is correlated with colorless cuticle. N-acetyltransferase (NAT) catalyzes the conversion of dopamine to N-acetyl dopamine (NADA) in cuticle tanning pathway. In this study, we studied function of TcNAT1 on adult cuticle tanning by double stranded-RNA (dsRNA) mediated gene silencing. Injection of dsTcNAT1 had no affect on animal development, growth and molting such as larva to larva, larva to pupa and pupa to adult. However, some of the resulting adults (~70%) showed split elytra that could not cover their abdomen, resulting in improper folding of their hindwings. Interestingly, body color of the mature adults (older than 3 days) was darker than that of control dsTcVer treated adults because probably due to the buildup of abnormally high levels of dopamine, which is used for dopamine eumelanin pigment synthesis (black pigment) and dopamine quinone-mediated protein crosslinking. On elytra and hindwings of these adults, darker pigments were observed around the sensory bristles that are located in the intervein regions, suggesting that NADA mediated b-sclerotization is occurred at these regions. Similarly, darker pigment was evident at veins of the hindwings of the dsTcNAT1-mature adults. These results suggest that TcNAT1 have important roles in sclerotization and pigmentation of adult body and wings (elytron and hindwing). This work was supported by NRF (NRF-2012R1A2A1A01006467).
