Genome-wide cardiac gene expression analysis of mice with cardiomyocyte-specific deletion of Dnmt3a and Dnmt3b

Cardiomyocyte-specific double knockout (DKO) mice lacking the catalytic domains of Dnmt3a (exon 18) and Dnmt3b (exon 19) were obtained by mating Dnmt3aflox and Dnmt3bflox mice [PMID 15757890] with mice expressing a cre recombinase under control of the cardiac atrial myosin light chain promoter (Myl7) [11689889]. Mice with the genotype Dnmt3aflox/flox, Dnmt3bflox/flox without expressing cre recombinase were used as control mice (CTL). Transcriptome analyses identified upregulation of 44 and downregulation of 9 genes in DKO as compared with control sham mice. TAC mice showed similar changes with substantial overlap of regulated genes compared to sham. Cardiac tissue from sham CTL (n=4) and DKO mice (n=4) as well as TAC-operated CTL (n=6) and DKO mice (n=6) was analysed.

本研究通过将携带Dnmt3aflox与Dnmt3bflox等位基因的flox小鼠[PMID 15757890]，与在心肌肌球蛋白轻链启动子（Myl7）调控下表达Cre重组酶（Cre recombinase）的小鼠[11689889]进行交配，成功构建了心肌细胞特异性缺失DNA甲基转移酶3a（Dnmt3a）外显子18（exon 18）与DNA甲基转移酶3b（Dnmt3b）外显子19（exon 19）催化结构域的双基因敲除（double knockout, DKO）小鼠。将基因型为Dnmt3aflox/flox、Dnmt3bflox/flox且不表达Cre重组酶的小鼠设为对照小鼠（CTL）。转录组分析结果显示，相较于假手术对照小鼠，DKO小鼠中存在44个基因上调、9个基因下调。经横向主动脉缩窄（transverse aortic constriction, TAC）造模的小鼠同样呈现出相似的基因表达变化，其差异调控基因与假手术组存在大量重叠。本研究对假手术对照小鼠（n=4）、DKO小鼠（n=4），以及经TAC处理的对照小鼠（n=6）和DKO小鼠（n=6）的心脏组织进行了分析。