Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
Open Biol. 2021 Oct;11(10):210121. doi: 10.1098/rsob.210121. Epub 2021 Oct 27.
Treslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here, we show that in egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin-MTBP is rate limiting for replication initiation. It is recruited onto chromatin before S phase starts and recruitment continues during S phase. We show that DDK activity both increases and strengthens the interaction of Treslin-MTBP with licensed chromatin. We also show that DDK activity cooperates with CDK activity to drive the interaction of Treslin-MTBP with TopBP1 which is a regulated crucial step in pre-initiation complex formation. These results suggest how DDK works together with CDKs to regulate Treslin-MTBP and plays a crucial in selecting which origins will undergo initiation.
Treslin/Ticrr 对于 DNA 复制的起始是必需的，并且与 MTBP（Mdm2 结合蛋白）结合。在这里，我们表明在卵提取物中，MTBP 与含有两种蛋白质分子的 Treslin 形成长的四聚体。免疫耗竭和添加回实验表明 Treslin-MTBP 是复制起始的限速因子。它在 S 期开始前被招募到染色质上，并且在 S 期内持续招募。我们表明 DDK 活性既增加又增强了 Treslin-MTBP 与许可染色质的相互作用。我们还表明 DDK 活性与 CDK 活性合作，驱动 Treslin-MTBP 与 TopBP1 的相互作用，这是起始前复合物形成的一个受调控的关键步骤。这些结果表明 DDK 如何与 CDKs 一起工作以调节 Treslin-MTBP，并在选择哪些起始原点将进行起始中起着关键作用。
