Molecular evolution of zebrafish dnmt3 genes and thermal plasticity of their expression during embryonic development

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• 作者：Catarina Campos^a ; ^b ; Luisa M.P. Valente^b ; Jorge M.O. Fernandes^a ; ^jfe@uin.no
• 关键词：20S ; twenty-somite stage ; ASXL2 ; additional sex combs-like protein 2 ; 尾2m ; beta-2-microglobulin ; BL ; blastula ; BU ; bud ; COMMD7 ; copper metabolism gene MURR1 domain containing 7 ; CH ; calponin-homology ; dN ; rate of nonsynonymous substitutions ; Dnmt ; DNA (c
• 刊名：Gene
• 出版年：2012
• 期刊代码：73_03781119
• 类别：bio
• 出版时间：25 May, 2012
• 卷：500
• 期：1
• 页码：93-100
• 文件大小：1811 K

摘要

DNA reprogramming by DNA (cytosine-5)-methyltransferases (m>dnmtsm>) after fertilisation is a dynamic mechanism that is essential for early development. Amongst the three types of m>dnmtm> genes in vertebrates, m>dnmt3m> is the one involved in de novo methylation and comprises three related genes, termed m>dnmt3am>, m>dnmt3bm> and m>dnmt3Lm> in mammals. Zebrafish (m>Danio reriom>) has six m>dnmt3m> paralogues, which have hitherto been termed m>dnmt3m> to m>dnmt8m>. Bayesian inference of phylogeny and synteny analysis revealed that m>dnmt6m> and m>dnmt8m> are in fact duplicated m>dnmt3am> genes, whereas the other paralogues are closely related to m>dnmt3bm>. Hence, we propose a revised nomenclature that more accurately reflects the relationship amongst zebrafish m>dnmt3m> genes. Both m>dnmt3am> genes were ubiquitously expressed in adult tissues, whilst the various m>dnmt3bm> paralogues were differentially expressed, with notably high expression levels in the gonads. The influence of embryonic temperature on m>dnmt3m> expression was investigated, since it is known to have a significant impact in early development and a long-term effect on growth in some teleost species. Embryos were incubated at 23, 27 or 31 掳C and samples collected at six developmental stages from blastula until protruding mouth. m>Dnmt3m> expression during early development was remarkably dynamic. In particular, mRNA levels of the two m>dnmt3am> genes showed a marked increase throughout development and several significant differences in m>dnmt3am> and m>dnmt3bm> transcript levels were found between temperatures at the same developmental point. Taken together, our data indicate that m>dnmt3m> paralogues are diverging and that m>dnmt3am> and m>dnmt3bm> may play different roles in thermal epigenetic regulation of gene expression during early development.