Developmental patterns of 3-hydroxykynurenine accumulation in white and various other eye color mutants of Drosophila melanogaster

Abstract

Several points of biochemical similarity between white and scarlet mutants suggest that both are defective in the transport of xanthommatin precursors. In both, accumulation of 3-hydroxykynurenine is negligible during larval life and occurs at only a slow rate during adult development. Larvae of both mutants also excrete 3H-3-hydroxykynurenine and 3H-kynurenine rapidly, which probably accounts for the normal levels of kynurenine during larval life. 3-Hydroxykynurenine levels are abnormal in all white mutants which were studied, although in two alleles which are strongly pigmented (w(sat) and w(col)) accumulation is enhanced rather than diminished. In w(a), larval accumulation is normal but accumulation during adult development is greatly diminished, suggesting that this mutation has a tissue-specific effect. Similar levels were found in zeste females. Of the 11 other eye color mutants tested, abnormal levels of 3-hydroxykynurenine were found in eight. In four of these (claret, light, lightoid, and pink), larval accumulation is negligible, suggesting that these have defects in the kynurenine transport system like scarlet and white. In three others, however (brown, karmoisin, and rosy), accumulation during larval life is enhanced. In cardinal accumulation is normal during larval life but is excessive during adult development. This evidence supports the suggestion that the cd mutation blocks the final step of xanthommatin synthesis.

Positional cloning of a Bombyx pink-eyed white egg locus reveals the major role of cardinal in ommochrome synthesis

“…The original Drosophila cardinal gene product has been regarded as a phenoxazinone synthase for converting 3-hydroxykynurenine into xanthommatin (Howells et al, 1977;Harris et al, 2011). Although both the Bombyx pe mutant and the Drosophila cardinal mutant seem to accumulate the ommochrome precursor 3-hydroxykynurenine (Supplementary Figure S6a, Inagami, 1954;Howells et al, 1977), it should be noted that they have different eye color phenotypes. Drosophila cardinal has reduced ommochrome levels at eclosion and becomes close to the wild-type compound eye color during aging, but the pink eyes of the Bombyx pe mutant do not become black like those of the wild type.…”

The influence of D. melanogaster mutations of the kynurenine pathway of tryptophan metabolism on locomotor behavior and expression of genes belonging to glutamatergic and cholinergic systems

“…В работе использовали следующие линии D. melanogaster: линия дикого типа Canton-S (CS) и мутанты КПОТ -vermilion (аллель v1), мутация гена трипто-фан-2,3-диоксигеназы, приводящая к отсутствию ки-нуренинов и накоплению триптофана (Linzen, 1974); cinnabar (аллель cn1), мутация структурного гена кину-ренингидроксилазы, блокирующая превращение кину-ренина в 3 ГК (Ghosh, Forrest, 1967;Warren et al, 1996) и приводящая к избытку КК (Ferri, 1983); cardinal (ал-лель cd1), мутация, приводящая к уменьшению активно-сти феноксазинонсинтетазы и 2,9-кратному накоплению 3-ГК по сравнению с диким типом (Howells et al, 1977). В результате 30 циклов скрещивания с линией CS все линии были приведены к единому генетическому фону.…”

“…У мутанта сardinal (cd, 3R: 94A1 94E2) инактивирован фермент распада 3-ГК феноксазинонсин-тетаза. Для cn показано двукратное увеличение содержа-ния КК (Ferre, 1983), для cd -2,9-кратное увеличение содержания 3-ГК (Howells et al, 1977) в тканях голов има-го. Накопление у мутантов метаболитов КПОТ имитирует их пролонгированное введение, что удобно для изучения механизмов физиологической активности кинуренинов.…”

The tryptophan oxidation pathway in mosquitoes with emphasis on xanthurenic acid biosynthesis

“…The chemical process and enzymes involved in this branch pathway of tryptophan metabolism have been studied extensively in mammals. Because metabolites in the tryptophan oxidation pathway influence the color of the compound eyes in insects, there have been a number of earlier reports discussing tryptophan metabolites in relation to insect compound eye development (Howells et al, 1977;Paton and Sullivan, 1978;Summers and Howells, 1978;Akaboshi, 1979;Howells, 1979). However, there have been few studies concerning the enzymes involved in the tryptophan oxidation pathway in insects.…”

“…KMO has a key role in tryptophan catabolism and the synthesis of ommochrome pigments in mosquitoes. Early studies of KMO were concerned primarily with its role in eye pigmentation in some insects, including D. melanogaster (Howells et al, 1977;Paton and Sullivan, 1978;Howells, 1979), Lucilia cuprina (Summers and Howells, 1978) and Musca domestica (Akaboshi, 1979). In D. melanogaster, the cinnabar (cn) gene (GenBank accession no.…”