Cell Cycle-Regulated Transcription of CENP-A by the MBF Complex Ensures Optimal Level of CENP-A for Centromere Formation
Cell Cycle-Regulated Transcription of CENP-A by the MBF Complex Ensures Optimal Level of CENP-A for Centromere Formation
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DOI：
10.1534/genetics.118.301745
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发表时间：
2019-03-01
期刊：
影响因子：
3.3
通讯作者：
Li, Fei
中科院分区：
文献类型：
--
作者：
Aristizabal-Corrales, David;Yang, Jinpu;Li, Fei
着丝粒在染色体分离中起重要作用。在大多数真核生物中，着丝粒由保守的组蛋白H3变体CENP-A表观遗传学定义。正确的着丝粒组装依赖于CENP-A水平的严格调节。CENP-A转录的细胞周期调控似乎是真核生物的普遍特征，但CENP-A转录的时间控制以及这种调控如何有助于着丝粒功能的分子机制仍然难以捉摸。CENP-A在裂殖酵母中已被证明在S期之前转录。使用各种同步化方法，我们证实CENP-A转录发生在G1，导致S期蛋白质几乎增加了两倍。通过遗传筛选，我们确定了MBF（MluI盒结合因子）复合物作为CENP-A转录时间控制的关键调节因子。CENP-A的周期性转录在MBF突变体中丢失，导致CENP-A错误定位和染色体分离缺陷。我们鉴定了CENP-A启动子中的MCB（MluI细胞周期盒）基序，并进一步表明MBF复合物与该基序结合，将CENP-A转录限制在G1期。MCB基序的突变导致组成型CENP-A表达和对细胞存活的有害影响。使用启动子驱动转录到不同的细胞周期阶段，我们发现CENP-A转录的时间是其着丝粒定位的时间。相反，我们的数据表明，细胞周期调节的CENP-A转录是确保跨代产生适量CENP-A的关键步骤。本研究提供了细胞周期依赖性CENP-A转录调控机制的见解，以及其对着丝粒功能的重要性。在大多数真核生物中，组蛋白H3变体CENP-A作为着丝粒的表观遗传标记。CENP-A转录受细胞周期调控，但调控的分子机制仍然难以捉摸。通过基因筛选
The centromere plays an essential role in chromosome segregation. In most eukaryotes, centromeres are epigenetically defined by the conserved histone H3 variant CENP-A. Proper centromere assembly is dependent upon the tight regulation of CENP-A level. Cell cycle regulation of CENP-A transcription appears to be a universal feature across eukaryotes, but the molecular mechanism underlying the temporal control of CENP-A transcription and how such regulation contributes to centromere function remains elusive. CENP-A in fission yeast has been shown to be transcribed before S phase. Using various synchronization methods, we confirmed that CENP-A transcription occurs at G1, leading to an almost twofold increase of the protein during S phase. Through a genetic screen, we identified the MBF (MluI box-binding factors) complex as a key regulator of temporal control of CENP-A transcription. The periodic transcription of CENP-A is lost in MBF mutants, resulting in CENP-A mislocalization and chromosome segregation defects. We identified the MCB (MluI cell cycle box) motif in the CENP-A promoter, and further showed that the MBF complex binds to the motif to restrict CENP-A transcription to G1. Mutations of the MCB motif cause constitutive CENP-A expression and deleterious effects on cell survival. Using promoters driving transcription to different cell cycle stages, we found that timing of CENP-A transcription is dispensable for its centromeric localization. Our data instead indicate that cell cycle-regulated CENP-A transcription is a key step to ensure that a proper amount of CENP-A is generated across generations. This study provides mechanistic insights into the regulation of cell cycle-dependent CENP-A transcription, as well as its importance on centromere function.In most eukaryotes, the histone H3 variant CENP-A serves as the epigenetic mark for centromeres. CENP-A transcription is subject to cell-cycle regulation, but the molecular mechanism underlying the regulation remains elusive. Through a genetic screen...