Combinatorial control of Spo11 alternative splicing by modulation of RNA polymerase II dynamics and splicing factor recruitment during meiosis
Combinatorial control of Spo11 alternative splicing by modulation of RNA polymerase II dynamics and splicing factor recruitment during meiosis
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DOI：
10.1038/s41419-020-2443-y
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发表时间：
2020-04-17
影响因子：
9
通讯作者：
Sette, Claudio
中科院分区：
文献类型：
--
作者：
Cesari, Eleonora;Loiarro, Maria;Sette, Claudio
减数分裂中的同源重组和染色体分离依赖于核酸内切酶SPO11的两种剪接变体（称为α和β）的及时表达，这两种变体分别跳过或包含外显子2。然而，尽管它的生理重要性，背后的机制Spo11选择性剪接减数分裂仍然是未知的。通过筛选预测结合Spo11可变剪接区的因子的活性，我们确定了hnRNPH作为小鼠精母细胞中SPO11 α剪接的关键调节因子。虽然hnRNPH没有上调伴随着开关在剪接减数分裂，其招聘Spo11前mRNA的选择性调制RNA聚合酶II（RNAPII）磷酸化和在外显子2附近的持续合成能力的青睐。hnRNPH结合位点位于促进SPO11 β剪接的剪接因子附近，表明hnRNPH通过竞争正调控因子而有利于外显子2跳跃。事实上，hnRNPH结合的Sam68，在体外和体内的SPO11 β剪接的正调节剂的共识基序的近端，它干扰Sam68的Spo11前mRNA的结合。因此，我们的工作表明，RNAPII动态调制与hnRNPH招聘发挥组合控制的适时调节Spo11剪接在减数分裂过程中。
Homologous recombination and chromosome segregation in meiosis rely on the timely expression of two splice variants of the endonuclease SPO11, named alpha and beta, which respectively skip or include exon 2. However, in spite of its physiological importance, the mechanism underlying Spo11 alternative splicing in meiosis is still unknown. By screening the activity of factors that are predicted to bind the alternatively spliced region of Spo11, we identified hnRNPH as a key regulator of SPO11 alpha splicing in mouse spermatocytes. Although hnRNPH was not upregulated in meiosis concomitantly with the switch in splicing, its recruitment to Spo11 pre-mRNA was favored by selective modulation of RNA polymerase II (RNAPII) phosphorylation and processivity in proximity of exon 2. The hnRNPH binding sites were localized near those of splicing factors that promote SPO11 beta splicing, suggesting that hnRNPH favors exon 2 skipping by competing out positive regulators. Indeed, hnRNPH binds proximal to a consensus motif for Sam68, a positive regulator of SPO11 beta splicing in vitro and in vivo, and it interferes with Sam68 binding to the Spo11 pre-mRNA. Thus, our work reveals that modulation of RNAPII dynamics in concert with hnRNPH recruitment exerts a combinatorial control of the timely regulated Spo11 splicing during meiosis.