TDP-43 Is a Transcriptional Repressor THE TESTIS-SPECIFIC MOUSE acrv1 GENE IS A TDP-43 TARGET IN VIVO
TDP-43 Is a Transcriptional Repressor THE TESTIS-SPECIFIC MOUSE acrv1 GENE IS A TDP-43 TARGET IN VIVO
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DOI：
10.1074/jbc.m110.166587
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发表时间：
2011-04-01
影响因子：
4.8
通讯作者：
Reddi, Prabhakara P.
中科院分区：
文献类型：
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作者：
Lalmansingh, Avin S.;Urekar, Craig J.;Reddi, Prabhakara P.
TDP-43是一种进化上保守的普遍表达的DNA/RNA结合蛋白。尽管最近的研究表明TDP-43与多种神经退行性疾病有关，但TDP-43的功能仍然知之甚少。在这里，我们使用精子发生作为模型系统来解决TDP-43的功能。我们以前表明，TDP-43结合到睾丸特异性小鼠acrv 1基因启动子在体外通过两个GTGTGT基序，这些基序的突变导致过早转录在精母细胞中，否则圆形精子特异性启动子。本研究验证了TDP-43抑制精母细胞acrv 1基因转录的假设。质粒染色质免疫沉淀证明TDP-43在体内通过GTGTGT基序与acrv 1启动子结合。报告基因分析表明，TDP-43抑制acrv 1核心启动子驱动的转录通过N-末端RRM 1结构域在组蛋白脱乙酰酶独立的方式。与阻遏物作用一致，生理分离的生殖细胞上的ChIP证实TDP-43占据精母细胞中的内源性acrv 1启动子。然而，令人惊讶的是，TDP-43仍然在圆形精子细胞，表达acrv 1 mRNA的启动子。我们发现，RNA结合缺陷TDP-43，但不是剪接变体亚型，减轻阻遏物的功能。从抑制性到活性组蛋白标记的转变对TDP-43占有率几乎没有影响。最后，我们发现，RNA聚合酶II的招聘，但暂停在acrv 1启动子在精母细胞。由于TDP-43位点的突变导致精母细胞在体内的过早转录，TDP-43可能参与暂停RNAPII在精母细胞中的acrv 1启动子。总之，我们的研究表明，TDP-43是一种转录抑制因子，它调节acrv 1基因在精子发生过程中的时空表达。
TDP-43 is an evolutionarily conserved ubiquitously expressed DNA/RNA-binding protein. Although recent studies have shown its association with a variety of neurodegenerative disorders, the function of TDP-43 remains poorly understood. Here we address TDP-43 function using spermatogenesis as a model system. We previously showed that TDP-43 binds to the testis-specific mouse acrv1 gene promoter in vitro via two GTGTGT-motifs and that mutation of these motifs led to premature transcription in spermatocytes of an otherwise round spermatid-specific promoter. The present study tested the hypothesis that TDP-43 represses acrv1 gene transcription in spermatocytes. Plasmid chromatin immunoprecipitation demonstrated that TDP-43 binds to the acrv1 promoter through GTGTGT motifs in vivo. Reporter gene assays showed that TDP-43 represses acrv1 core promoter-driven transcription via the N-terminal RRM1 domain in a histone deacetylase-independent manner. Consistent with repressor role, ChIP on physiologically isolated germ cells confirmed that TDP-43 occupies the endogenous acrv1 promoter in spermatocytes. Surprisingly, however, TDP-43 remains at the promoter in round spermatids, which express acrv1 mRNA. We show that RNA binding-defective TDP-43, but not splice variant isoforms, relieve repressor function. Transitioning from repressive to active histone marks has little effect on TDP-43 occupancy. Finally, we found that RNA polymerase II is recruited but paused at the acrv1 promoter in spermatocytes. Because mutation of TDP-43 sites caused premature transcription in spermatocytes in vivo, TDP-43 may be involved in pausing RNAPII at the acrv1 promoter in spermatocytes. Overall, our study shows that TDP-43 is a transcriptional repressor and that it regulates spatiotemporal expression of the acrv1 gene during spermatogenesis.