Wojciechowski Marek, Rafalski Dominik, Kucharski Robert, Misztal Katarzyna, Maleszka Joanna, Bochtler Matthias, Maleszka Ryszard
Laboratory of Structural Biology, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
Open Biol. 2014 Aug;4(8). doi: 10.1098/rsob.140110.
In mammals, a family of TET enzymes producing oxidized forms of 5-methylcytosine (5mC) plays an important role in modulating DNA demethylation dynamics. In contrast, nothing is known about the function of a single TET orthologue present in invertebrates. Here, we show that the honeybee TET (AmTET) catalytic domain has dioxygenase activity and converts 5mC to 5-hydroxymethylcytosine (5hmC) in a HEK293T cell assay. In vivo, the levels of 5hmC are condition-dependent and relatively low, but in testes and ovaries 5hmC is present at approximately 7-10% of the total level of 5mC, which is comparable to that reported for certain mammalian cells types. AmTET is alternatively spliced and highly expressed throughout development and in adult tissues with the highest expression found in adult brains. Our findings reveal an additional level of flexible genomic modifications in the honeybee that may be important for the selection of multiple pathways controlling contrasting phenotypic outcomes in this species. In a broader context, our study extends the current, mammalian-centred attention to TET-driven DNA hydroxymethylation to an easily manageable organism with attractive and unique biology.
在哺乳动物中，一个产生5-甲基胞嘧啶（5mC）氧化形式的TET酶家族在调节DNA去甲基化动力学方面发挥着重要作用。相比之下，对于无脊椎动物中单个TET直系同源物的功能却一无所知。在此，我们表明蜜蜂TET（AmTET）催化结构域具有双加氧酶活性，并且在HEK293T细胞试验中将5mC转化为5-羟甲基胞嘧啶（5hmC）。在体内，5hmC的水平取决于条件且相对较低，但在睾丸和卵巢中，5hmC约占5mC总水平的7-10%，这与某些哺乳动物细胞类型的报道相当。AmTET存在可变剪接，在整个发育过程以及成年组织中高度表达，在成年大脑中表达最高。我们的研究结果揭示了蜜蜂基因组修饰的另一个灵活层面，这可能对于该物种中控制相反表型结果的多种途径的选择很重要。在更广泛的背景下，我们的研究将目前以哺乳动物为中心对TET驱动的DNA羟甲基化的关注扩展到了一种具有吸引人且独特生物学特性的易于管理的生物体。
