Natural Variation in TBP-ASSOCIATED FACTOR 4b Controls Meiotic Crossover and Germline Transcription in Arabidopsis
Natural Variation in TBP-ASSOCIATED FACTOR 4b Controls Meiotic Crossover and Germline Transcription in Arabidopsis
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DOI：
10.1016/j.cub.2019.06.084
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发表时间：
2019-08-19
期刊：
影响因子：
9.2
通讯作者：
Henderson, Ian R.
中科院分区：
文献类型：
--
作者：
Lawrence, Emma J.;Gao, Hongbo;Henderson, Ian R.
减数分裂交换频率在基因组内变化，影响遗传多样性和适应性。反过来，种群内的遗传变异可以起到修改交叉频率在顺式和反式。为了确定控制减数分裂交叉频率的遗传变异，我们筛选拟南芥种质使用荧光重组报告。我们映射了一个遗传修饰的交叉频率在Col x Bur群体的拟南芥TBP相关因子4 b（TAF 4 b），它编码的RNA聚合酶II的一般转录因子TFIID的亚基内的提前终止密码子。拟南芥taf 4 b突变是在不列颠群岛发现的一种罕见变异，起源于西南爱尔兰。利用遗传学、基因组学和免疫细胞学，我们证明了taf 4 b交叉在全基因组范围内的减少，在亚端粒区域的减少最强烈。使用纯化的性母细胞的RNA测序（RNA-seq），我们表明TAF 4 b表达是性母细胞富集的，而其副产物TAF 4广泛表达。与TFIID在促进基因表达中的作用一致，野生型和taf 4 b性母细胞的RNA-seq鉴定了广泛的转录变化，包括调节减数分裂细胞周期和重组的基因。因此，TAF 4 b复制与减数分裂细胞特异性表达的获得和生殖系转录的促进相关，其直接或间接地起作用以提高交换。这确定了一种新的模式减数分裂重组控制通过一个通用的转录因子。
Meiotic crossover frequency varies within genomes, which influences genetic diversity and adaptation. In turn, genetic variation within populations can act to modify crossover frequency in cis and trans. To identify genetic variation that controls meiotic crossover frequency, we screened Arabidopsis accessions using fluorescent recombination reporters. We mapped a genetic modifier of crossover frequency in Col x Bur populations of Arabidopsis to a premature stop codon within TBP-ASSOCIATED FACTOR 4b (TAF4b), which encodes a subunit of the RNA polymerase II general transcription factor TFIID. The Arabidopsis taf4b mutation is a rare variant found in the British Isles, originating in South-West Ireland. Using genetics, genomics, and immunocytology, we demonstrate a genome-wide decrease in taf4b crossovers, with strongest reduction in the sub-telomeric regions. Using RNA sequencing (RNA-seq) from purified meiocytes, we show that TAF4b expression is meiocyte enriched, whereas its paralog TAF4 is broadly expressed. Consistent with the role of TFIID in promoting gene expression, RNA-seq of wild-type and taf4b meiocytes identified widespread transcriptional changes, including in genes that regulate the meiotic cell cycle and recombination. Therefore, TAF4b duplication is associated with acquisition of meiocyte-specific expression and promotion of germline transcription, which act directly or indirectly to elevate crossovers. This identifies a novel mode of meiotic recombination control via a general transcription factor.