Study of mechanisms that decrease speed of replication fork progression in DNA damage response

2016 Fiscal Year Final Research Report

• Project/Area Number: 25440009
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Molecular biology
• Research Institution: Nara Institute of Science and Technology
• Principal Investigator: Akiyama Masahiro 奈良先端科学技術大学院大学, バイオサイエンス研究科, 准教授 (80273837)
• Co-Investigator(Renkei-kenkyūsha): Maki Hisaji 奈良先端科学技術大学院大学, バイオサイエンス研究科, 教授 (20199649) ; Katayama Tsutomu 九州大学, 薬学研究科(研究院), 教授 (70264059)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: DNA複製 / 複製フォーク / DNA損傷応答 / SOS応答 / 一分子解析 / DNAコーミング / DNAポリメラーゼ / DNA組換え酵素

Outline of Final Research Achievements

When replication fork progression is aberrant, genome becomes instable by replication stress, leading to pathological disorders. Thus, the DNA damage response ensures genomic stability under replication stress. However, the dynamics of fork movements in cells and impact of the damage response on the dynamics remains unknown in any organism. To approach these problems in Escherichia coli cells, I had developed a new technique to accurately measure fork speed in the cells. Here, using the technique, we found that speed distribution of individual forks is relatively uniform but contains three subpopulations that have different speeds. A major determinant of fork speed was DNA polymerase (Pol) III in the replication machinery. Furthermore, onset of the DNA damage response uniformly decreased speed of individual forks. The slowdown mechanism was operated by detachment of the major speed determinant, Pol III, from forks by DinB (pol IV), and a noble function of RecA recombinase.

Free Research Field

分子生物学