Motohashi Kazunori A, Morita Naoki, Kato Atsushi, Saito Tamao
Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan.
Biosci Biotechnol Biochem. 2012;76(9):1672-6. doi: 10.1271/bbb.120183. Epub 2012 Sep 7.
The signalling molecule 1-(3,5-dichloro-2,6-dihydroxy-4-methoxyphenyl) hexan-1-one (DIF-1) is required for differentiation and pattern formation in Dictyostelium discoideum development. DIF-1 is synthesized by three enzymes, a hybrid polyketide synthase, a flavin-dependent halogenase, and a des-methyl-DIF-1 methyltransferase. The genome data on the related species D. purpureum are now public. Using this genome information, des-methyl-DIF-1 methyltransferase of D. purpureum was identified, and was named Dp dmtA. Overexpression of Dp dmtA complemented the defects in basal disc formation and lower cup formation in a dmtA knock-out mutant of D. discoideum. This indicates that Dp dmtA has the same function as D. discoideum dmtA and compensates for loss of the dmtA gene in the D. discoideum dmtA mutant. The materials released in the medium by D. purpureum contained stalk-inducing activity with the same retention time as that of DIF-1 in HPLC fractionation. This indicates that the stalk-inducing signal of DIF-1 and des-methyl-DIF-1 methyltransferase are conserved in D. purpureum.
信号分子1-(3,5-二氯-2,6-二羟基-4-甲氧基苯基)己烷-1-酮（DIF-1）是盘基网柄菌发育过程中细胞分化和模式形成所必需的。DIF-1由三种酶合成，一种杂合聚酮合酶、一种黄素依赖性卤化酶和一种去甲基-DIF-1甲基转移酶。相关物种紫柄盘基网柄菌的基因组数据现已公开。利用这些基因组信息，鉴定出了紫柄盘基网柄菌的去甲基-DIF-1甲基转移酶，并将其命名为Dp dmtA。在盘基网柄菌dmtA基因敲除突变体中，Dp dmtA的过表达弥补了基盘形成和下杯形成的缺陷。这表明Dp dmtA与盘基网柄菌dmtA具有相同的功能，并能补偿盘基网柄菌dmtA突变体中dmtA基因的缺失。紫柄盘基网柄菌在培养基中释放的物质具有茎诱导活性，在高效液相色谱分离中的保留时间与DIF-1相同。这表明DIF-1的茎诱导信号和去甲基-DIF-1甲基转移酶在紫柄盘基网柄菌中是保守的。
