研究成果の紹介
バイオサイエンス研究科植物生殖遺伝学研究チームのDiana M Buzas博士が日本遺伝学会第84回大会Best Paper特別審査員賞を受賞
バイオサイエンス研究科植物生殖遺伝学研究チームのDiana Buzas博士（博士研究員）が2012年9月24日-26日に九州大学にて開催された「日本遺伝学会 第84回大会」において、「Best Paper特別審査員賞」を受賞しました。受賞の対象となった発表は「DNA de-methylation in Arabidopsis thaliana female gametophyte: is DEMETER alone?」です。
日本遺伝学会では国際化の試みとして、セッションのすべてを英語で行う国際セッションが今回初めて導入されました。そのセッションの中からBest Paper賞が一題選ばれ特別審査員賞が授与されました。
受賞時の発表内容（21世紀の遺伝学IX GSJコミュニケーションより転記）
Cytosine methylation can have a significant contribution to epigenetic control of gene expression in plants as well as animals. While being considered a stable, heritable modification of DNA, cytosine methylation may also undergo dynamic changes during development. DNA replication can either propagate or dilute out the methylated cytosines, and in addition, enzymatic removal and alteration also take place. Identification of DNA de-methylating enzymes is greatly complicated by the fact that such components are often lethal when mutated and also they act in small developmental windows, often in the gametes.
In Arabidopsis thaliana, DEMETER, a DNA glycosylase, is believed to act before fertilization in a single cell of the female gametophyte (termed central cell, coloured in blue in Figure B, left) and de-methylate a set of genes via the base excision repair pathway, thus facilitating their maternal specific transcriptional activation.
The central cell divides after fertilization to generate the endosperm, the placenta equivalent (coloured in blue Figure B, right), which also expresses maternal genes. When a demeter mutation is inherited by the female gametophyte, endosperm divisions do take place initially, however later they abort (Figure B, brown seeds are heterozygote mutant, normal seeds are segregating wild-type).
The transcriptional activation of specific genes in the central cell and endosperm in wild type, as well as the lack of such activation in the demeter mutant have been used as recognizable hallmarks of DNA de-methylation. Such hallmarks are easiest visualized with a GFP reporter placed under the control of native DNA region directing maternal gene expression (Figure E). We mutagenized such a line and identified other DNA de-methylating components.
References
Choi et al 2002, Cell
Kinoshita et al, 2004 Science
（2013年03月29日掲載）
