| 1. |
- Li, Shuqi, et al.
(författare)
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Rtt105 functions as a chaperone for replication protein A to preserve genome stability
- 2018
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Ingår i: EMBO Journal. - : Wiley-VCH Verlagsgesellschaft. - 0261-4189 .- 1460-2075. ; 37:17
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Tidskriftsartikel (refereegranskat)abstract
- Generation of single-stranded DNA (ssDNA) is required for the template strand formation during DNA replication. Replication Protein A (RPA) is an ssDNA-binding protein essential for protecting ssDNA at replication forks in eukaryotic cells. While significant progress has been made in characterizing the role of the RPA-ssDNA complex, how RPA is loaded at replication forks remains poorly explored. Here, we show that the Saccharomyces cerevisiae protein regulator of Ty1 transposition 105 (Rtt105) binds RPA and helps load it at replication forks. Cells lacking Rtt105 exhibit a dramatic reduction in RPA loading at replication forks, compromised DNA synthesis under replication stress, and increased genome instability. Mechanistically, we show that Rtt105 mediates the RPA-importin interaction and also promotes RPA binding to ssDNA directly in vitro, but is not present in the final RPA-ssDNA complex. Single-molecule studies reveal that Rtt105 affects the binding mode of RPA to ssDNA These results support a model in which Rtt105 functions as an RPA chaperone that escorts RPA to the nucleus and facilitates its loading onto ssDNA at replication forks.
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| 2. |
- Yu, Chuanhe, et al.
(författare)
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A mechanism for preventing asymmetric histone segregation onto replicating DNA strands
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 361:6409, s. 1386-+-
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Tidskriftsartikel (refereegranskat)abstract
- How parental histone (H3-H4)2 tetramers, the primary carriers of epigenetic modifications, are transferred onto leading and lagging strands of DNA replication forks for epigenetic inheritance remains elusive. Here we show that parental (H3-H4)2 tetramers are assembled into nucleosomes onto both leading and lagging strands, with a slight preference for lagging strands. The lagging strand preference increases markedly in cells lacking Dpb3 and Dpb4, two subunits of the leading strand DNA polymerase, Pol ε, due to the impairment of parental (H3-H4)2 transfer to leading strands. Dpb3-Dpb4 binds H3-H4 in vitro and participates in the inheritance of heterochromatin. These results indicate that different proteins facilitate the transfer of parental (H3-H4)2 onto leading vs lagging strands, and that Dbp3-Dpb4 plays a significant role in this poorly understood process.
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