Telomere Biology and RNA-DNA hybrids

1 PhD project offered in the IPP summer call 2021

Scientific background

Telomeres shorten every cell division cycle and this eventually leads to replicative senescence. Senescence can prevent cancer from developing, however the accumulation of senescent cells also drives premature ageing. Therefore, the loss of telomeres must be regulated to ensure that cells do not enter senescence too rapidly. We have recently described that a non-coding RNA at telomeres (TERRA) plays a critical role in regulating senescence through the formation of RNA-DNA hybrids (R-loops). The molecular details regarding how TERRA R-loops function, remains unknown.

PhD project: DNA replication fidelity at telomeres with R-loops

Our hypothesis is that stable RNA-DNA hybrids promote homology directed repair at short telomeres once they are encountered by the DNA replication machinery. We also hypothesize that the critical signal to promote this signal is DNA replication pausing or stress. We will use chromatin immunoprecipitation (ChIP) of DNA polymerases as well as repli-seq to study DNA replication timing at telomeres when they are short and long, as well as when they have an accumulation of R-loops. In addition, we will use 2D-gel electrophoresis to detect DNA replication pausing at telomeres. We will also use cancer relevant mutants of DNA polymerase Epsilon that have reduced processivity, in order to understand how replication velocity may affect repair of R-loop harboring telomeres. This project will use cutting edge sequencing, molecular biology and yeast genetics to address these critical questions, which are highly relevant for both ageing and cancer biology.

Publications relevant  to this project

Niehrs C* and Luke B* (2020) Regulatory R-loops as facilitators of gene expression and genome stabilityNat Rev Mol Cell Biol, 21:167–178 (*indicates joint contribution) Link

Pérez-Martínez L, Öztürk M, Butter F# and Luke B# (2020) Npl3 stabilizes R-loops at telomeres to prevent accelerated replicative senescenceEMBO Rep, 21:e49087 (#indicates joint correspondance) Link

Lockhart A, Pires VB, Bento F, Kellner V, Luke-Glaser S, Yakoub G, Ulrich HD and Luke B (2019) RNase H1 and H2 are differentially regulated to process RNA-DNA hybridsCell Rep, 29:2890–2900.e5 Link

Graf M*, Bonetti D*, Lockhart A*, Serhal K, Kellner V, Maicher A, Jolivet P, Teixeira MT and Luke B (2017) Telomere length determines TERRA and R-loop regulation through the cell cycleCell, 170:72–85 (*indicates joint contribution) Link

Balk B*, Maicher A*, Dees M, Klermund J, Luke-Glaser S, Bender K and Luke B (2013) Telomeric RNA-DNA hybrids affect telomere-length dynamics and senescenceNat Struct Mol Biol, 20:1199–1205 (*indicates joint contribution) Link

Contact

Prof. Brian Luke
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