Functions of Melanogenesis-Related Genes by Chemical and Biochemical Methods

哺乳动物的黑色素在化学上有两种不同的形态：棕色到黑色的真黑素和黄色到红色的真黑素。黑色素的生成受到许多基因的影响，其产物的水平决定了黑色素产生的数量和质量。为了研究不同毛色基因对小鼠毛囊黑素细胞合成黑色素化学性质的影响，我们引入了区别溶解黑素和棕色型真黑素的新方法。我们应用这些和之前开发的高效液相色谱和分光光度方法来分析不同突变小鼠的黑色素：黑色、致命黄色、活性黄色、刺鼠黑色素、棕色、浅色、白化、稀释色、隐性黄色、粉红色眼稀释色、板条色和银色。结果表明：1)黑色素在Soluene-350中的完全增溶是估算黑色素总量的简便方法；2)致死黄色、活性黄色和隐性黄色毛发含有几乎纯的黑色素；3)棕色、浅色、银色和粉眼黑发的黑色素具有共同的化学性质，其特征是在强碱中部分溶解。我们认为：1)棕色型真黑素的聚合度低于黑色型真黑素；2)板条状头发黑色素中含有的5，6-二羟基吲哚-2-羧酸衍生单元的比例比黑色和其他真黑色素要低得多。这些结果表明，我们的方法，高效液相色谱和分光光度法相结合，可能有助于对毛囊黑素细胞产生的黑色素进行化学表征。

Mammalian melanins exist in two chemically distinctforms : the brown to black eumelanins and the yellow to reddish pheomelanins. Melanogenesis is influenced by a number of genes, the levels of whose products determine the quantity and quality of the melanins produced. To examine the effects of various coat-color genes on the chemical properties of melanins synthesized in the follicular melanocytes of mice, we have introduced new methods to solubilize differentially pheomelanins and brown -type eumelanins. We applied these and previously developed HPLC and spectrophotometric methods for assaying eu- and pheomelanins to characterize melanins in various mutant mice : black, lethal yellow, viable yellow, agouti, brown, light, albino, dilute, recessive yellow, pink-eyed dilution, slaty, and silver. It was demonstrated that 1) complete solubilization of melanins in Soluene-350 is a convenient method to estimate the total amount of eu- and pheomelanins, 2) lethal yellow, viable yellow, and recessive yellow hairs contain almost pure pheomelanins, and 3) melanins from brown, light, silver, and pink-eyed black hairs share chemical properties in common that are characterized by partial solubility in strong alkali. We suggest that 1) the brown-type eumelanins have lower degrees of polymerization than the black-type eumelanins, and 2) slaty hair melanin contains a greatly reduced ratio of 5,6-dihydroxyindole-2-carboxylic acid-derived units as compared with black and other eumelanic hair melanins. These results indicate that our methodology, HPLC and spectrophotometric methods combined, may be useful in chemically characterizing melanin pigments produced follicular melanocytes.