RRC ID 555
Author Futahashi R, Fujiwara H.
Title Melanin-synthesis enzymes coregulate stage-specific larval cuticular markings in the swallowtail butterfly, Papilio xuthus.
Journal Dev Genes Evol
Abstract Like the adult wing, butterfly larvae are unique in their coloring. However, the molecular mechanisms underlying the formation of insect larval color patterns are largely unknown. The larva of the swallowtail butterfly Papilio xuthus changes its color pattern markedly during the 4th ecdysis. We investigated its cuticular color pattern, which is thought to be composed of melanin and related pigments derived from tyrosine. We cloned three enzymes involved in the melanin-synthesis pathway in P. xuthus: tyrosine hydroxylase (TH), dopa decarboxylase (DDC), and ebony. Whole-mount in situ hybridization showed that the expression of both TH and DDC is strongly correlated with the black markings. ebony is strongly expressed only in the reddish-brown area. The expression pattern of each enzyme coincides with the cuticular color pattern of the subsequent instar. We also investigated the uptake of melanin precursors into cultured integument. Inhibition of either TH or DDC activity prevents in vitro pigmentation completely. Addition of dopamine to integuments in the presence of TH inhibitor causes overall darkening without specific markings. From these results, specific larval cuticular color patterns are regulated by stage-specific colocalization of enzymes in epidermal cells rather than by the differential uptake of melanin precursors into individual epidermal cells. Epidermal cells expressing TH and DDC, but not ebony, produce the black cuticle, and epidermal cells expressing TH, DDC, and ebony produce the reddish-brown cuticle.
Volume 215(10)
Pages 519-29
Published 2005-10-1
DOI 10.1007/s00427-005-0014-y
PMID 16133568
MeSH Animals Base Sequence Blotting, Northern Butterflies / enzymology* Butterflies / growth & development Cloning, Molecular Cluster Analysis DNA Primers Dopa Decarboxylase / genetics Dopa Decarboxylase / metabolism* Dopamine / pharmacology Epidermis / metabolism* Gene Expression* In Situ Hybridization Larva / enzymology Larva / growth & development Molecular Sequence Data Phylogeny* Pigmentation / drug effects Pigmentation / physiology* Sequence Analysis, DNA Tyrosine 3-Monooxygenase / antagonists & inhibitors Tyrosine 3-Monooxygenase / genetics Tyrosine 3-Monooxygenase / metabolism*
IF 1.339
Times Cited 76