Pelletier M K, Murrell J R, Shirley B W
Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0406, USA.
Plant Physiol. 1997 Apr;113(4):1437-45. doi: 10.1104/pp.113.4.1437.
As part of an ongoing investigation into the organization and regulation of the flavonoid biosynthetic pathway, two Arabidopsis thaliana expressed sequence tag (EST) clones (153O10T7 and YAY780) with high homology to leucoanthocyanidin dioxygenase (LDOX) or flavonol synthase (FLS) were identified. EST YAY780 was sequenced and found to encode a protein 49 to 78% identical to all LDOX sequences in the database. EST 153O10T7 was used to isolate a genomic clone encoding a protein with 59 to 61% sequence identity to petunia (Petunia hybrida) and potato (Solanum tuberosum) FLS. DNA blot analysis was used to screen the Arabidopsis genome for sequences related to FLS and LDOX and to determine the positions of the two clones on the RI map. The expression patterns of FLS and LDOX in etiolated seedlings moved to white light and in two putative regulatory mutants (ttg and tt8) were determined by RNA blot analysis. These studies indicate that FLS is an "early" flavonoid gene in Arabidopsis seedlings, whereas LDOX is a "late" gene. Furthermore, FLS is the first flavonoid enzyme identified in Arabidopsis that may be encoded by a gene family.
作为对类黄酮生物合成途径的组织和调控进行的一项正在进行的研究的一部分，鉴定出了两个与无色花青素双加氧酶（LDOX）或黄酮醇合酶（FLS）具有高度同源性的拟南芥表达序列标签（EST）克隆（153O10T7和YAY780）。对EST YAY780进行了测序，发现其编码的蛋白质与数据库中所有LDOX序列的同一性为49%至78%。EST 153O10T7被用于分离一个基因组克隆，该克隆编码的蛋白质与矮牵牛（Petunia hybrida）和马铃薯（Solanum tuberosum）的FLS的序列同一性为59%至61%。DNA印迹分析用于筛选拟南芥基因组中与FLS和LDOX相关的序列，并确定这两个克隆在RI图谱上的位置。通过RNA印迹分析确定了FLS和LDOX在转移到白光下的黄化幼苗以及两个假定的调控突变体（ttg和tt8）中的表达模式。这些研究表明，FLS是拟南芥幼苗中的一个“早期”类黄酮基因，而LDOX是一个“晚期”基因。此外，FLS是拟南芥中鉴定出的第一个可能由基因家族编码的类黄酮酶。
