Phylogeny of tyrosinase gene

高等动物的体色主要是由黑色素决定的。这种色素沉积在一种叫做黑素体的细胞器中，黑素体是一种特殊分化的细胞。酪氨酸酶是黑素体蛋白之一，是黑素合成的关键酶。这些目标之一是发现transacting因子，保证协调基因表达的metanization ;我们迄今为止已经检测到两个蛋白质分子结合5个不同的基因，这两个基因都编码黑素体蛋白的调控序列。本文报道了日本鹌鹑和鳄龟两个非哺乳动物酪氨酸酶基因的克隆和序列测定，发现日本鹌鹑和鳄龟酪氨酸酶基因的5'上游区、第一外显子和部分第一内含子的序列与高等动物的序列同源性不高。虽然前导序列的相似性相对较低，但第一外显子在假定的起始位点和外显子/内含子边界的核苷酸位置上都高度保守，这些非哺乳动物酪氨酸酶基因的调控区是否能在哺乳动物黑素细胞中发挥作用是一个有趣的问题。要回答这个问题，就要从阐明动物黑素细胞的进化保守性（或形成性）开始。

Body color of higher animals is primarily determined by melanin pigment. The pigment is deposited in an organelle called melanosome in a specifically differentiated cell, melanosome. Tyrosinase is one of melanosomal proteins and well known as the key enzyme for melanin pigment biosynthesis.In this report, two closely interrelated aspects are focused. One of those aims is to discover transacting factors which guarantee coordinate gene expression for metanization ; We have so far detected two protein molecules which bind 5 regulatory sequences of two different genes which both code melanosomal proteins. Another aspect is to commence studying emergence and evolutionary track of melanocyte.Here we report cloning and sequencing of two non-mammalian tyrosinase genes from Japanese quail and snap turtle.Genomic sequences of tyrosinase genes which contain 5' upstream regions, the first exons and a part of the first introns from Japanese quail and a snap turtle did not show high homology to those of higher animals. Although there were relatively low similarity seen at the leader sequences, the first exons were highly conserved both at the nucleotide position of putative initiation sites and the exon/intron border.It is interesting to see whether or not those regulatory region of non-mamalian tyrosinase genes can function in mammalian melanocytes. To answer such a question commence to elucidate the evolutionary conserved(or formed)identity of melanocyte in animals.