ジャーナル: Mol Cell / 年: 2023 タイトル: How Pol α-primase is targeted to replisomes to prime eukaryotic DNA replication. 著者: Morgan L Jones / Valentina Aria / Yasemin Baris / Joseph T P Yeeles / 要旨: During eukaryotic DNA replication, Pol α-primase generates primers at replication origins to start leading-strand synthesis and every few hundred nucleotides during discontinuous lagging-strand ...During eukaryotic DNA replication, Pol α-primase generates primers at replication origins to start leading-strand synthesis and every few hundred nucleotides during discontinuous lagging-strand replication. How Pol α-primase is targeted to replication forks to prime DNA synthesis is not fully understood. Here, by determining cryoelectron microscopy (cryo-EM) structures of budding yeast and human replisomes containing Pol α-primase, we reveal a conserved mechanism for the coordination of priming by the replisome. Pol α-primase binds directly to the leading edge of the CMG (CDC45-MCM-GINS) replicative helicase via a complex interaction network. The non-catalytic PRIM2/Pri2 subunit forms two interfaces with CMG that are critical for in vitro DNA replication and yeast cell growth. These interactions position the primase catalytic subunit PRIM1/Pri1 directly above the exit channel for lagging-strand template single-stranded DNA (ssDNA), revealing why priming occurs efficiently only on the lagging-strand template and elucidating a mechanism for Pol α-primase to overcome competition from RPA to initiate primer synthesis.
全体 : Human replisome bound by pol alpha, engaged on a fork DNA substra...
全体
名称: Human replisome bound by pol alpha, engaged on a fork DNA substrate with a 60 nucleotide lagging strand.
要素
複合体: Human replisome bound by pol alpha, engaged on a fork DNA substrate with a 60 nucleotide lagging strand.
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超分子 #1: Human replisome bound by pol alpha, engaged on a fork DNA substra...
超分子
名称: Human replisome bound by pol alpha, engaged on a fork DNA substrate with a 60 nucleotide lagging strand. タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#21
由来(天然)
生物種: Homo sapiens (ヒト)
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実験情報
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構造解析
手法
クライオ電子顕微鏡法
解析
単粒子再構成法
試料の集合状態
particle
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試料調製
緩衝液
pH: 7.6
凍結
凍結剤: ETHANE
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
撮影
フィルム・検出器のモデル: GATAN K3 BIOQUANTUM (6k x 4k) 平均電子線量: 37.8 e/Å2