Howells A J, Summers K M, Ryall R L
Biochem Genet. 1977 Dec;15(11-12):1049-59. doi: 10.1007/BF00484496.
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.
白色和猩红色突变体之间的几个生化相似点表明，两者在黄蝶呤前体的转运方面存在缺陷。在这两种突变体中，3-羟基犬尿氨酸在幼虫期的积累可以忽略不计，在成虫发育过程中也仅以缓慢的速度积累。这两种突变体的幼虫也会迅速排泄3H-3-羟基犬尿氨酸和3H-犬尿氨酸，这可能是幼虫期犬尿氨酸水平正常的原因。在所研究的所有白色突变体中，3-羟基犬尿氨酸水平都不正常，尽管在两个色素沉着强烈的等位基因（w(sat) 和w(col)）中，积累增加而非减少。在w(a)中，幼虫期的积累正常，但成虫发育过程中的积累大大减少，这表明这种突变具有组织特异性效应。在zeste雌性中也发现了类似的水平。在测试的其他11种眼色突变体中，有8种发现了3-羟基犬尿氨酸水平异常。其中4种（酒红色、浅色、类浅色和粉红色）在幼虫期的积累可以忽略不计，这表明它们在犬尿氨酸转运系统中存在缺陷，类似于猩红色和白色突变体。然而，在其他3种（棕色、卡莫辛和玫瑰色）中，幼虫期的积累增加。在基数突变体中，幼虫期的积累正常，但在成虫发育过程中过多。这一证据支持了cd突变阻断黄蝶呤合成最后一步的观点。
